Versatile water-floated nanostructures for three-dimensional nanotransfer printing

Domain: biology
Published: 2026-03-30
Editorial outcome: minor_revision

Abstract
Integrating functional nanostructures onto diverse three-dimensional surfaces is important for a wide range of applications, including holography, sensors, and extended reality. Nanotransfer printing (nTP) has emerged as a leading approach owing to its high throughput and resolution. However, conventional nTP techniques often require toxic solvents, adhesives, or thermal treatments, which limit the range of compatible substrates. Here, we introduce a water-floating-based nanotransfer printing (WF-nTP) technique inspired by hydrographic printing. In WF-nTP, nanostructures are floated on water and transferred onto target substrates via a scooping process. WF-nTP enables conformal transfer of Au, Pt, Pd, and Ni nanomeshes onto diverse substrates, including curved optical lenses, fibers, and plant leaves with micro-/nanoscale roughness. The technique also supports transfer onto hydrophobic surfaces by modulating the surface tension of the water bath. To highlight process versatility, two representative applications are demonstrated: the fabrication of multilayer SERS nanomesh fabrication for pesticide detection and the integration of Pd nanomeshes onto electrospun fibers for sensitive hydrogen sensing. Overall, WF-nTP provides a straightforward, substrate-independent route for nanostructure transfer with broad potential in advanced sensing and display technologies.

Introduction
The rapidly advancing field of next-generation nanotechnology is gaining considerable attention as it seeks to implement nanostructures on various two-dimensional and three-dimensional (3D) surfaces, expanding the range of applications in various areas, such as chemical 1, 2, 3 and physical sensors 4, 5, 6, metamaterials 7, optical devices 8, 9, and surface-enhanced Raman scattering (SERS) 10, 11, 12. Conventional techniques have been extensively employed to fabricate nanostructures on a variety of substrates. Bottom-up approaches, such as self-assembly 13, chemical vapor deposition (CVD) 14, atomic layer deposition (ALD) 15, are effective for synthesizing nanomaterials at the atomic or molecular level. However, they often require material- and substrate-specific processing conditions such as high vacuum pressure, high temperature, or toxic chemicals, which limit their flexibility for direct pattern transfer onto diverse substrates that are vulnerable to such conditions. By contrast, top down approaches, including e-beam lithography 16, focused-ion beam lithography 17, nanoimprint lithography 18, and nanotransfer printing (nTP) 19, 20, enable the direct fabrication of pre-defined nanostructures onto a wide variety of target surfaces. Among these methods, nTP distinguishes itself through its cost-effectiveness, high throughput, high process speed, high spatial resolution, reliability, and ability to accommodate diverse materials and morphologies 21. The fundamental mechanism of nTP relies on controlling interfacial adhesion forces between the mold, substrate, and target material 21. Successful transfer of the patterned nanostructure to the substrate occurs when the adhesion force between the target material and mold (F mold) is weaker than that between the target material and substrate (F substrate); i.e., F substrate – F mold < 0. Two primary approaches are generally employed to facilitate nTP: enhancing F substrate or reducing F mold. F substrate can be enhanced by adding an adhesive layer between the substrate and target material, exploiting the thermoplastic properties of the substrate 22, 23, or using a nanowelding process 24, 25. However, this approach necessitates altering the inherent properties of the substrate by introducing additives, applying pressure, or increasing temperature, potentially compromising the preservation of the original substrate characteristics. Conversely, F mold can be reduced by lubricating the interface between the mold and target material with a solvent 19 or employing a mold dissolution process 3. Although this strategy does not require excessive substrate deformation or adding extraneous materials, it often involves toxic solvents and additional steps to remove solvent-soluble layers. In addition, both approaches face challenges associated with the rigidity of the mold, which hinders conformal contact with substrates, particularly those with 3D curved surfaces. Consequently, the increasing demand for nanostructure transfer methods that are independent of substrate properties and avoid toxic or potentially damaging processes necessitates a simple and direct transfer technique that is well suited for curved surfaces.

This study proposes an nTP technique inspired by hydrographic printing. Hydrographic printing typically involves floating ink and transferring it onto a submerged object. Based on this process, the nanostructure is floated on water and transferred to a substrate through a “scooping up” process. This process can be performed in three stages, as shown in Fig. 1(a). Fig. 1(a-i) illustrates the proposed concept, which involves plasma etching a metal-deposited nanopatterned mesh mold, weakening F mold. When immersed in water, the etched gaps generate vacancies, allowing water to penetrate and separate the mesh from the mold. Subsequently, the suspended mesh floats on the water (Fig. 1(a-ii)) and can be easily transferred to curved surfaces. As previously mentioned, the transfer mechanism is straightforward. Fig. 1(a-iii) presents the mechanism for transferring nanostructures onto curved 3D substrates through the “scooping up” method. During the drying process, the progressive evaporation of water reduces the size of the liquid meniscus formed between the gold nanomesh and the substrate. This reduction in meniscus size leads to an increase in its curvature, thereby significantly enhancing the capillary forces that pull the mesh into intimate contact with the substrate and promote strong, short-range adhesion 26, 27, 28, 29. Once the water has completely evaporated, the mesh remains stably adhered to the substrate through van der Waals forces, which are maximized by the close contact established during the capillary-driven process. In other words, the capillary action serves to bring the nanomesh and substrate surfaces into exceedingly close proximity, thereby maximizing the van der Waals interaction. The versatility of water-floating nanotransfer printing (WF-nTP) has been demonstrated on various 3D substrates, such as curved optical lenses and plant leaves with micro/nanoscale roughness. The metal nanomesh conformed to these surfaces without defects. Notably, this technique allows transfer onto hydrophobic surfaces, including the backs of leaves, thermoplastic polyurethane (TPU) fibers, and superhydrophobic lotus surfaces, by adjusting the surface tension of the water bath. This method enables the transfer of nanostructures onto a wide range of substrates without requiring adhesives or additional energy.

The proposed WF-nTP technique offers significant advantages, particularly for transferring nano-scale materials onto curved surfaces. Unlike conventional hydrographic printing, which is restricted to macro-scale decorative patterns on water-soluble films such as PVA, our WF-nTP method enables the transfer of high-resolution nanoscale structures directly onto various substrates. This advancement eliminates the need for sacrificial PVA layers and chemical activators, significantly reducing process complexity and the risk of polymer residue contamination. For further comparison, the metal-independent nTP method proposed by Hwang et al. uses a self-assembled monolayer (SAM) layer and requires covalent bonding with an adhesive coating at temperatures of at least 150 °C to transfer metals onto flat and curved surfaces 30. Miyamoto et al. developed a simpler approach using water-soluble polyvinyl alcohol (PVA) electrospun (ES) fibers as a sacrificial material, enabling the transfer of Au nanowires to various surfaces, including human skin, by washing the PVA with water 31. However, this method relies on sacrificial layers that may introduce residue and process complexity. By contrast, the WF-nTP technique eliminates the need for adhesive layers, toxic solvents, thermal energy, or sacrificial materials, allowing the metal nanomesh to float directly on water and be transferred via a simplified, residue-free process. Therefore, the nanostructure can be easily transferred onto curved surfaces by simply scooping them in a water bath, making the process simpler and more versatile.

Using this versatile transfer technique, two representative applications were demonstrated, as illustrated in Fig. 1(b). A surface-enhanced Raman spectroscopy (SERS) mesh was first demonstrated using multilayer nanomeshes. The optimal number of layers was confirmed through finite-difference time-domain (FDTD) simulations and validated using Raman spectra measurements of Rhodamine 6G (R6G). For practical applications, the mesh was transferred onto a leaf and fruit for nondestructive pesticide detection. In addition, a Pd-based mesh was successfully transferred onto ES TPU fibers to create a hydrogen gas sensor. This sensor, benefiting from the ability of palladium to detect hydrogen gas through reversible transformation, maintained the gas permeability of the fiber even after the nTP process. Consequently, it demonstrated sensitive and reliable detection under a 1 % hydrogen concentration.

Results
Fabrication and various morphological analyses of the transferred nanostructures
Fabrication of the water floated Au nanomesh is illustrated in Supplementary Figure 1. The Au-deposited polyurethane acrylate (PUA) mold was first prepared. A square-dot replica PUA mold was obtained from the square-mesh patterned master mold through a nanoimprinting process. Subsequently, Au-deposited the PUA mold was fabricated using e-beam evaporation. Supplementary Figure 2 shows the photographic images on this process. For the nanomesh to float on water as illustrated in Fig. 2a, Au mesh was first separated from the PUA mold through selective plasma etching. Before plasma etching, the square dots were removed using a metal-independent nanotransfer printing technique developed by the authors’ group. This process successfully removed the upper square dots from the mold, as shown in Fig. 2(b-i) and Supplementary Figure 3. Subsequently, the optimal plasma etching time was determined by examining its effects on the PUA mold. Notably, as shown in Fig. 2(b-ii to b-iv), the width of the square dot region of PUA decreases with increasing etching time, reducing the adhesion force between the Au mesh and mold. Because PUA is more vulnerable to plasma than gold, the width of the PUA mold decreases with increasing etching time without damaging the Au. When the etching time exceeds 5 min, the Au mesh begins to suspend, with the mold fully collapsing after 20 min. Therefore, an optimal etching time of 20 min enables effective detachment of the Au mesh from the mold, as the adhesion force between them is nearly completely eliminated, weakening F mold. This creates a vacancy between the mold and Au, allowing water penetration and facilitating the separation of the Au mesh from the mold when immersed in water. The minimum thickness required for the mesh to stably float on water is 20 nm, allowing the ultrathin nanomesh to float on the water surface, as illustrated in Fig. 2(c). Films thinner than 20 nm, particularly near 10 nm, exhibit severe embrittlement due to smaller grain size and reduced plastic deformation capacity. This results in a high density of cracks and brittle fractures during deformation 32, causing such thin films to hardly float on water. In contrast, 20 nm films retain sufficient ductility to withstand the floating and transfer process, establishing 20 nm as the practical lower limit for stable nanomesh flotation. Then, the mesh was transferred onto a slide glass for morphological analysis, confirmed through scanning electron microscopy (SEM) imaging, as shown in Fig. 2(d). Fig. 2(e) shows the energy-dispersive spectroscopy (EDS) mapping of various materials and mesh structures, highlighting the diversity of the materials and mesh configurations. Given that the WF-nTP process requires a plasma etching step, the choice of metals is limited to those resistant to oxidation. Notably, various oxidation-resistant metals, such as Ni, Pt, and Pd, along with different mesh patterns, such as holes and cross-dots, can also float on water and be transferred onto substrates. For successful and stable floating, the nanostructure must be laterally interconnected. Mesh-type geometries such as square mesh, hole arrays, cross-dot grids) maintain mechanical integrity on the water surface and prevent uncontrolled drifting. In addition, the WF-nTP technique enables multilayer stacking. Fig. 2(f) shows the SEM images of a three-layer stack on a glass slide. Once the mesh fully dries after being lifted from the water bath, it remains stably attached to the substrate owing to capillary-driven strong van der Waals forces, even when submerged in water again. This high stability enables further nTP processes on pre-transferred substrates, allowing multiple mesh layers, rather than just a monolayer, to be transferred onto the desired substrate.

Results of nTP on various 3D surfaces
To demonstrate the applicability of the developed nTP technique to 3D or curved surfaces, the Au mesh was transferred onto an optical lens with varying radii of curvature, as illustrated in Fig. 3(a). Because WF-nTP does not require any adhesive or supporting substrate, the mesh coule be transferred onto a curved 3D surface simply by scooping it in water. The Au mesh was successfully transferred onto the curved surface regardless of the curvature radius. To verify the integrity of the mesh structure on the lens, an optical microscope (OM) was used to record a video (Supplementary Movie 1) while sweeping the focus across 6, which is the most curved surface. Each region was individually scanned to assess the fine structure of the mesh. The video confirmed that the mesh retained its original structure across the entire lens surface. To further verify crack-free transfer on the lens, the electrical resistance at each edge point of the Au mesh was measured. Au meshes with thicknesses of 20, 40, 80, and 100 nm were transferred onto four lenses with different radii of curvature, and the resistance was measured by placing the probe in contact with the edge of each mesh, as shown in Fig. 3(b) and Supplementary Figure 4. The results indicated that the electrical resistance remained consistent across lenses with the same Au thickness, confirming crack-free contact despite varying radii of curvature. As anticipated, the resistance decreased with increasing Au thickness in all cases.

The versatile WF-nTP method also demonstrates significant advantages when transferring nanostructures onto thermally and mechanically sensitive substrates, such as plant leaves. Considering the micro- and nanoscale roughness of plant leaves, including numerous curved surfaces, the versatility of WF-nTP was examined by applying it to a Nandina domestica leaf. Fig. 3(c) shows a photographic image of the leaf with single-layer and three-layered Au meshes. SEM analysis was performed to compare the morphological characteristics of the mesh on the leaf, beginning with the raw leaf surface, as shown in Fig. 3(d-i) and (d-ii). The raw leaf surface exhibited rough textures and irregular curvature distributions. However, upon transferring the Au mesh, it conformally adhered to the rough surfaces of the leaf without significant defects, as presented in Fig. 3(d-iii) and (d-iv). The surface tension and capillary force during the drying process facilitated this successful adhesion, enabling the Au mesh to firmly adhere to the surface. In addition, multilayer stacking was achieved on the leaf, even over the curved regions, as shown in Fig. 3(d-v) and (d-vi). Relatively low magnification SEM images are also presented in Supplementary Figure 5 (a-c) to demonstrate that a large area could be covered. To further validate the conformity of the mesh to the leaf surface, cross-sectional images showing different mesh thicknesses were obtained, as shown in Fig. 3(e). The yellow line represents the Au mesh, which conformally follows the original contours of the curved leaf surface. To quantify the bending radius corresponding to the elastic limit of the mesh structure, we performed COMSOL simulations on a single unit cell of the mesh. The detailed simulation methods are provided in Supplementary Methods part. From the simulation, the bending radius corresponding to the elastic limit for the 20 nm thick Au mesh was estimated to be approximately 800 nm, as shown in Supplementary Figure 6. However, it is important to note that this result reflects only the local mechanical behavior of an individual unit cell and does not fully capture the characteristics of the entire mesh, which is composed of an array of such cells. To better understand the practical bending behavior, we analyzed the cross-section of the plant surface shown in Fig. 3(e) through image processing to calculate curvature and radius of curvature (Supplementary Figure 7). This analysis revealed that the smallest radius of curvature on the plant surface was about 280 nm. Interestingly, the Au mesh was able to conformally bend over surfaces with radii of curvature smaller than the bending radius corresponding to the elastic limit estimated by the single unit cell simulation. This observation indicates that the array architecture of the mesh imparts greater flexibility than what is predicted by the unit cell model alone, enabling the mesh to adapt to highly curved surfaces more effectively. Furthermore, even when the local radius of curvature of the plant surface is below 300 nm, the Au can still be transferred without fracture due to its intrinsic ductility and ability to undergo local plastic deformation. As a result, the 20 nm-thick Au mesh maintains overall mechanical integrity and conformability through plastic deformation rather than purely elastic deformation, enabling successful transfer even on surfaces with curvatures sharper than the theoretical elastic limit. In the case of 3-layer mesh as depicted in Supplementary Figure 5(d), 3 layers of mesh also conformally formed along the original surface. Beyond morphological analysis of conformal contact on the leaf, electrical impedance spectroscopy (EIS) was also conducted, as shown in Supplementary Figure 8. Since biological surfaces such as plant leaves exhibit both resistive and capacitive behavior, EIS is more suitable than simple surface resistance measurements. It provides information on electrical properties of both the surface and internal structure including moisture content and ion distribution, therefore EIS is widely used to monitor plant health 33. Given that stable and clear impedance measurements require electrodes to conform closely to the surface, we compared a conventional clip electrode with a single-layer Au mesh electrode transferred via WF-nTP. Both showed stable signals over a broad frequency range (1 to 105 Hz), but the Au mesh consistently exhibited lower impedance at all frequencies, as shown in Supplementary Figure 8(a). In phase angle spectra, the clip electrode showed some noise, whereas the Au mesh produced very clear signals, as provided in Supplementary Figure 8(b). These results demonstrate that the Au mesh produced by WF-nTP was conformally transferred onto the plant surface. In addition, the stability of the mesh on the leaf was assessed by comparing its surface morphology before and after showering (Supplementary Movie 2). During the showering process, the yellow mesh preserved its original structure without cracks. To confirm this result at the microscopic level, SEM analysis was performed on the 1-layer mesh before and after showering, as shown in Supplementary Figure 9. Notably, no significant defects or damage such as large holes, fractures, or distortions were observed after showering, indicating that the mesh was robust and firmly adhered to the leaf. While minor defects typical in ultrathin nanostructure on rough natural surfaces may exist, these did not affect the overall structural integrity or electrical performance of the mesh. These results confirm that the WF-nTP method is particularly advantageous for transferring various functional nanopatterned metals onto rough surfaces, demonstrating excellent mechanical stability even under strong water exposure. To further demonstrate the versatility of the WF-nTP technique, apple and orange substrates were used for transfer. Fig. 3(f) shows photographic and optical microscopy (OM) images of the apple with the transferred mesh. The faint yellow square indicates the successfully transferred mesh, as verified by the OM images. The brighter region represents the mesh, and the inset shows a magnified view, confirming its structural integrity. Similarly, Fig. 3(g) shows photographic and SEM images of the mesh on an orange, further demonstrating the broad applicability of this method.

Results of nTP on various hydrophobic surfaces
The wetting properties of the target substrate with the liquid in the bath are critical to the WF-nTP process. In the previously discussed experiments using water as the transfer medium, WF-nTP was successfully performed on hydrophilic surfaces, such as glass slides and the front side of the leaf. However, challenges may arise when transferring nanostructures onto hydrophobic surfaces. For instance, the back side of the Nandina domestica leaf is hydrophobic, as illustrated in Supplementary Figure 10. The contact angle on the back side of the leaf exceeds 90 °, with a significantly higher roughness compared with the glass slide and the front side of the leaf, both of which have contact angles below 90 °. When the contact angle exceeds 90 °, nTP cannot be implemented because the repellent force of the liquid prevents mesh transfer. To address this challenge, the transfer medium (i.e., liquid in the bath) must be strategically adjusted. The contact angle between the substrate and liquid depends on the vapor above the free surface of the liquid, as well as the nature of the liquid and solid in contact. In this experiment, because the substrate and vapor layer are fixed variables, the contact angle can be reduced by altering the liquid, specifically by adjusting its surface tension. Water, which has a relatively high surface tension compared with many other liquids, is not an ideal transfer medium for hydrophobic surfaces. However, mixing ethanol with water significantly reduces the surface tension of the solution 34. This reduction in surface tension enables the modification of the contact angle on the back side of the leaf. Fig. 4(a) shows the contact angles of different solutions with varying ethanol-to-water volume ratios. As the ethanol volume fraction increases, the contact angle decreases, indicating improved wettability on the back side of the leaf.

Based on these findings, the Au mesh was floated on each solution. The reduced contact angle enabled the successful transfer of the Au mesh onto the hydrophobic surfaces. However, when the ethanol volume fraction exceeded 30%, the Au mesh could no longer float on the surface of the solution owing to the excessively low surface tension 34. This indicates that a specific surface tension is necessary to float the target materials and wet the substrate at low contact angles. The optimal liquid medium composition for hydrophobic surfaces was determined to be an 80/20 (v v^-1) water/ethanol mixture, exhibiting a surface tension of approximately 42.9 mN m^-1 34. Subsequently, the Au mesh was transferred onto the back side of the leaf using the optimized water/ethanol mixture. As shown in Fig. 4(b), the mesh conformally adhered to the hydrophobic surface without cracks or fractures.

To further verify the versatility of the substrate, ES TPU fibers were fabricated and used as another example of a hydrophobic surface 23. As shown in Fig. 4(c), the contact angle variation with changing ethanol-to-water volume ratios exhibited a similar trend for the ES TPU fibers. Fig. 4(d) shows the successful transfer of the Au mesh onto the fibers. To further validate conformal transfer, a cross-sectional image is shown in Supplementary Figure 11. Conventional nTP methods for thermoplastic substrates such as TPU typically require thermal energy and high pressure, potentially damaging and deforming the substrate. However, the WF-nTP was successfully implemented without the need for thermal energy or pressure. Finally, the Au mesh was successfully transferred onto a lotus leaf, known for its superhydrophobic properties 35, by adjusting the liquid medium composition. Fig. 4(e) presents the variation in the contact angle of the lotus for each mixture with OM images depicting water droplets exhibiting high contact angles on the lotus leaf. However, when water was replaced with a water/ethanol mixture, the lotus leaf became wettable, and the Au mesh was successfully transferred onto the lotus surface. Supplementary Figure 12 shows the photographic image of lotus with water droplet on the leaf. The lotus surface is composed of complex hierarchical pillar structures that contribute to its super-hydrophobicity, as shown in Fig. 4(f) 36, 37. Despite its structural complexity and superhydrophobicity, the Au mesh conformed to the surface through the developed WF-nTP. Relatively low-magnification SEM images of the lotus leaf with and without the Au mesh are shown in Supplementary Figure 13. This demonstrates that the substrate-independent WF-nTP technique is a universal and straightforward method for transferring metal nanostructures across various surfaces.

Design and demonstration of a SERS device for pesticide detection
A significant advantage of the WF-nTP method is its ability to facilitate multiple stacking of nanostructures on versatile substrates. Once the mesh is transferred and dried, it stably adheres to the substrate without detaching, enabling repeated transfers. Stacking several nanomeshes creates numerous hot spots for SERS between the layers. Fig. 5(a) shows two representative hotspot types: horizontal and vertical. When the square meshes are stacked, gaps are formed in the horizontal and vertical directions, particularly for more than three layers. Although the positions of the horizontal gaps are uncontrollable owing to the random orientation during WF-nTP, this randomness can still generate numerous horizontal nanogaps. By contrast, the vertical gaps are easily controlled because they correspond to the thickness of each layer. Gaps with sizes less than 100 nm, particularly under 20 nm 38, can serve as hotspots for SERS. The thinnest stable Au mesh that can float on water is 20 nm thick, making it ideal for this application. The optimal number of layers for SERS was determined through FDTD simulations. The detailed simulation methods are provided in Supplementary Methods part. Fig. 5(b) shows a 3D schematic of the multilayered nanomesh used in the simulation. The mesh units are stacked along the z-axis, and the laser wave is polarized along the x-axis. A 2D monitor was placed in the x-z plane across the layers. As shown in Fig. 5(c), the maximum e-field enhancement increases with up to seven layers, creating three distinct vertical gaps along each vertical line. The major local enhancements occur between the topmost and third layers (first vertical gap), particularly between the third and fifth layers (second vertical gap). However, when the number of layers increases to nine, the maximum e-field enhancement decreases compared with that in the seven-layer configuration, as shown in Fig. 5(f). This reduction can be attributed to the diminished ability of the laser to effectively penetrate the uppermost layers. In addition, the inconsistent e-field enhancement can be attributed to wave interference as it propagates through the multiple stacked layers. This interference can be either constructive or destructive, leading to a nonuniform distribution of e-field enhancement across the mesh structure 10. Consistent with the literature on multi-stacked nanostructures for SERS 10, a two-layer stack can sometimes show a lower maximum enhancement than a single layer because additional interfaces introduce destructive interference. Our three-layer calculation exhibits the same trend, resulting in a smaller e-field enhancement than the single-layer case. To assess the robustness of this conclusion against horizontal layer alignment, additional FDTD calculations for four representative in-plane registries between adjacent meshes across 2 to 9 layers were performed, with detailed results shown in Fig. S14. Given that the possible combinations of alignment cases are unlimited, we cannot simulate every possible alignment configuration. Therefore, we performed simulations for several representative and limited scenarios. We believe these simulations adequately capture the overall trend observed in the multi-layer stacking effects on hot spot distribution and field enhancement. As a result, while horizontal misalignment redistributes the hotspot locations, the maximum e-field enhancement still displays a clear optimum near 6 to 7 layers, consistent with the trends observed in Fig. 5c and Fig. 5f. This suggests that the layer-dependent optimum is determined primarily by the interplay between vertical coupling and field attenuation from multiple interfaces, rather than any specific in-plane alignment. It should be noted that a direct one-to-one correspondence between simulated enhancement and measured SERS intensity is not expected. The experimental measurement integrates signals from both horizontal and vertical hotspot arrays within a finite illuminated area. These factors, together with finite optical attenuation through the upper layers, explain why the simulated three-layer case can yield a lower maximum e-field enhancement than the single layer while the experimental Raman intensity for three layers can differ from the trend of the idealized vertical gap model. Despite these complexities, the overall behavior aligns with the previous study 10 and our supplementary alignment study in Fig. S14, supporting the conclusion that an optimal layer count of approximately seven exists for the present mesh geometry.

Directly correlating these results with the experimentally measured SERS intensity is complex owing to the integrated effect of various hotspots (horizontal and vertical gap arrays). However, the overall trend can be compared 10. The Raman signal of R6G, a representative material for SERS substrate evaluation, was measured on a glass slide with a seven-layer mesh, as shown in Fig. 5(d) 39, 40, 41. R6G was detected at concentrations ranging from 10-3 M to 10-6 M using the seven-layer mesh. To evaluate the uniformity of the Raman signal across the substrate, measurements were taken at six different points on the mesh surface for each concentration. As shown in Fig. S15, the Raman spectra obtained at these multiple locations exhibited consistent peak patterns and intensities, indicating a uniform signal distribution. The Raman signal of 10-6 M R6G was also measured as a function of the number of layers, as shown in Fig. 5(e). Notably, the Raman intensity of R6G increased up to the seven-layer mesh but decreased with the nine-layer mesh, consistent with the simulated values. Fig. 5(f) also illustrates that the trend in the SERS intensity as a function of the number of layers is consistent with the simulation results, although minor discrepancies are noted in the three-layer configuration. This suggests that a seven-layer mesh is the optimal condition for SERS in a 20 nm Au mesh system.

For practical applications, a seven-layer Au mesh was transferred onto the leaf and fruit of a lemon-orange tree for pesticide detection, as shown in Fig. 5(g). The meshes conformed well to the surfaces of both substrates. Because leaves and fruits are sensitive to high temperatures and pressures, the WF-nTP method offers significant advantages for these applications. This technique enables direct and rapid printing without damaging the surface, enabling the simple and nondestructive detection of pesticides on leaves and fruits using SERS 42, 43, 44, 45, 46. This study used thiram (tetramethylthiuram disulfide), a commonly used pesticide, for demonstration purposes. Detecting thiram residues on fruits is crucial because they pose health risks to humans. For this purpose, 1 mM and 100 µM thiram solutions in water were drop-cast over a 1 cm² area on the leaf and fruit. Fig. 5(h) shows the characteristic Raman spectra of thiram on the leaf and fruit. Notably, without the seven-layer mesh, no characteristic thiram peaks are detected on either the raw leaf or fruit. However, after applying the seven-layer mesh, the peaks are observed in both cases. With the seven-layer mesh, the characteristic carotenoid peak in the raw fruit and leaf are detected at 1154 cm⁻¹, attributed to C–C stretching, while no significant peaks are observed in the raw cases 47. For thiram, four characteristic peaks are identified in the fruit and leaf samples. The peaks at 437 and 560 cm⁻¹ corresponded to C=S and S–S stretching, respectively. In addition, the peaks at 928 and 1386 cm⁻¹ are attributed to C=S and C–N stretching 48, 49. These results indicate that the seven-layer mesh effectively enhanced the Raman signal. Notably, the detection limits varied between the leaf and fruit: 1 mM and 100 µM for the leaf and fruit, respective. This discrepancy can be attributed to the more complex surface morphology and curvature of the fruit, which can create additional hot spots for SERS, as shown in Fig. S16. These results indicate that the seven-layer Au meshes enhance the SERS signal, and surface morphology plays a crucial role. According to the EU pesticides database 50, the permissible pesticide residue levels for humans range from 22 µg cm^-2 to 31 µg cm^-2. The maximum detection limit for thiram on the leaf was 1 mM; however, the calculated amount was 6.49 µg cm^-2, five times lower than the permissible level. Therefore, the WF-nTP method demonstrates significant potential for application in SERS devices, particularly in the agricultural industry.

Demonstration of Pd-based hydrogen gas sensor
A demonstration of the versatility of the WF-nTP process, a Pd mesh was transferred onto an ES TPU fiber substrate and used as a hydrogen gas sensor. ES TPU fibers are widely used for their suitability for creating stretchable masks and sportwear and their ease of integration into commercial clothing, enabling the creation of smart fabrics. In addition to the existing functions of ES fiber-based smart fabrics, such as hypoglycemia and diabetes diagnosis 23, wound monitoring, and healing 51, 52, the WF-nTP technique has been employed to create Pd-based hydrogen gas sensors on TPU fibers. When Pd is exposed to hydrogen gas, it undergoes a reversible transformation into palladium hydride (PdHx), increasing electrical resistance 3. This change in resistance provides a straightforward mechanism for detecting hydrogen gas. Fig. 6(a) schematically illustrates the structure of the Pd-based hydrogen gas sensor formed on electrospun fibers, showing how the mesh interacts with incoming hydrogen molecules. Fig. 6(b) presents a photographic image of the sensor placed inside the gas-testing chamber along with a corresponding SEM image, confirming the morphology and integration of the Pd mesh with the fiber substrate. In this study, the relative change in the sensor resistance was tested for hydrogen gas concentrations ranging from 0.25 % to 1 %. As shown in Fig. 6(c), the sensor response increases with the hydrogen gas concentration, with the relative resistance of the Pd mesh reflecting these changes. The gas sensor benefits from the stable transfer of the thin 100 nm Pd nanomesh, which enhances sensor sensitivity, and the sufficient permeability of the TPU fibers to hydrogen gas, enabling rapid gas absorption and desorption. This combination enables the clear detection of hydrogen concentrations below 1%. To further validate the stability and repeatability of the sensor, a 50-cycle test was performed for each concentration. As shown in Fig. 6(d), the sensor demonstrates consistent responses with minimal variation, indicating the stable transfer of the Pd mesh onto the ES TPU fibers using WF-nTP. Finally, the gas selectivity of the sensor was evaluated by exposing it to various gases, including carbon monoxide (CO), hydrogen sulfide (H₂S), and nitrogen dioxide (NO₂), at different concentrations. As shown in Fig. 6(e), the sensor exhibits negligible responses to these gases, at concentrations exceeding those permitted by the Occupational Safety and Health Administration (OSHA) guidelines 3. These results confirm that the Pd-based sensor has superior selectivity for hydrogen gas over other potential interference gases, as provided in Fig. S17. These findings suggest that the proposed WF-nTP process has significant potential for applications in the gas sensor field and the development of smart fabrics.

Methods
Sample Fabrication
(1) Nanopatterned Mold Fabrication: A Si master with various mesh structures was designed using krypton fluoride lithography to prepare a sacrificial nanopatterned polymer mold. RM-311 polyurethane UV-curable resin (Minuta Technology Co., Korea) was poured onto the prepared Si master mold and sealed with a UV-transparent polyethylene terephthalate (PET) film. Proper pressure was applied to the PET film using a commercial handy roller to ensure that the resin fully covered the nanopatterned master mold. The resin was exposed to UV light at a peak wavelength of 365 nm for 90 s before being separated from the master. Various types of nanopatterned molds can be fabricated by following this procedure using different Si master molds, as shown in Supplementary Figure 2.

(2) Floating Nanostructures on Water: From the mesh type Si master mold, the dot type PUA mold was replicated through nanoimprinting process. Target materials, including Au, Pd, Pt, and Ni, were deposited on the nanopatterned mold using an e-beam evaporation system (Daeki Hi-Tech Co., Korea). Then, the top dot side of target materials was removed. Previously, the authors developed a metal-independent nTP technique using trichloro(1H,1H,2H,2H-perfluorooctyl) silane as the SAM 30. A SAM layer, used as an adhesive to remove the top dot side of the target material, was spin-coated onto the wafer. The target material was then pressed onto the SAM-coated wafer on a hot plate at 150 °C. After 4 min, the mold was released from the wafer. During this process, the target materials on the top dot side were removed, as depicted in Supplementary Figure 3. Afterwards, the mold was subjected to a 20-minute O2/CF4 plasma treatment at 100 W power, with an O2 flow rate of 98 sccm and CF4 at 20 sccm, to selectively etch the PUA mold, leading to the suspension of the target material on the bottom mesh side.

(3) Nanotransfer Printing on Various Substrates: The plasma-etched mold with the target material was immersed in a water bath. After plasma etching, the target material was suspended, creating a gap between the target material and mold that facilitated water penetration. Subsequently, the nanomesh was separated from the PUA mold and floated on the water surface. The water-floating nanomesh could be transferred to various surfaces, such as glass slides, optical lenses, plant leaves, and fruits, by simply scooping it up. The nanomesh achieved conformal contact when the remaining water completely evaporated. Supplementary Figure 1 illustrates these three steps. All chemical agents and EtOH (≥99.50% purity) were purchased from Sigma-Aldrich (USA). Optical lenses were purchased from Edmund Optics (USA). All fruits and plant leaves were purchased from a local market in Daejeon, Korea.

Characterization
A focused-ion beam integrated scanning electron microscope (SEM, Helios Nanolab™, FEI, Netherlands) was used to investigate the cross-section images with varying plasma etching times and verify the conformal transfer of the mesh to the leaf surface. Ultra-high-resolution SEM combined with energy-dispersive spectroscopy (EDS, SU8230, Hitachi, Japan) was employed to measure the morphology of various nTP substrates and transferred mesh structures. The radius of curvature of the optical lens was measured using a radius indicator (EDongguan Yongchuan Equipment Co., Ltd, China). A digital multimeter (Fluke 15B+, Fluke Corporation, USA) was used to measure the electrical resistance of the mesh on the curved lens based on the Au thickness. The water contact angle on the glass slide and leaf and the water/EtOH mixture contact angle on the back side of the leaf were measured using contact angle detection equipment (KRÜSS Scientific, Germany).

Electrical impedance spectroscopy measurement
Electrical impedance spectroscopy (EIS) was performed on plant leaves using both a conventional metal clip electrode and a single-layer Au mesh electrode transferred via WF-nTP. The measurements, conducted over a frequency range of 1 Hz to 10⁵ Hz with 0.1V using a commercial impedance analyzer (PalmSens4, PalmSens, Netherlands) compared impedance magnitude and phase angle under identical conditions.

Pesticide residue conversion
The surface residue density ρ surf is defined as the applied mass per wetted surface area and was calculated as:
ρ surf [μg cm−2] = (C sol [mM] × V applied [μL] × 0.24043) / A wet [cm2]
where, 0.24043 converts mM and μL to μg using the molar mass of thiram (M = 240.43 g mol⁻¹). C sol is the thiram concentration in solution, V applied is the dispensed volume, and A wet is the wetted area measured.

Raman measurement
R6G and thiram were purchased from Sigma-Aldrich (USA) and dissolved in EtOH and water, respectively. R6G solutions with concentrations ranging from 10-3 M to 10-6 M and thiram solutions with concentrations of 10-3 M and 10-4 M were prepared. R6G and thiram solution were drop-casted on the multilayered mesh structure (27 µl 1 cm^-2) and dried. The Raman shift was collected for 60 s using a dispersive Raman spectrometer (ARAMIS, Horiba, France) equipped with a 785 nm laser. Gratings with 1200 grooves mm^-1 and a × 50 microscope were used to focus the laser onto the sample.

Gas-sensing measurement
Gas-sensing experiments were performed in a sealed chamber equipped with a probe. Real-time resistance was monitored using a Keithley 2635 B source meter (Tektronix, Inc., USA). Mass flow controllers (MFCs) were used to control the gas concentration and flow rate. The source meter and MFCs were managed using the LabVIEW interface. During the tests, the resistance change was recorded by alternating the flow of hydrogen gas and nitrogen at 1000-second intervals. Selectivity tests were performed using nitrogen dioxide, carbon monoxide, and hydrogen sulfide.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "This manuscript reports the fabrication of metallic mesh structures via a water-floating-based nanotransfer printing (nTP) technique. In this technique, the metallic mesh is floated on a water surface and subsequently transferred onto a target substrate using a scooping procedure. By modulating the surface tension through the addition of ethanol, the metallic mesh can be effectively transferred even onto hydrophobic and topographically complex surfaces such as lotus leaves. The Au and Pd meshes exhibit functionality as flexible SERS substrates and hydrogen gas sensors, respectively. Although the replicated PUA mold may not be reusable, the water-floating-based nanotransfer technique may offer advantages in terms of cost-effectiveness, high throughput, time efficiency, and process reliability, while circumventing toxic or substrate-damaging procedures. However, the article is not entirely satisfactory in terms of clarity, particularly concerning the clarity of responses to technical questions. Therefore, I cannot recommend the publication of this manuscript without addressing these concerns, which are detailed below.\nBottom of Page 1: These fabrication strategies fall under the category of top-down approaches. The authors are encouraged to introduce bottom-up approaches for constructing two- and three-dimensional nanostructures and compare them with top-down approaches in terms of their respective advantages and limitations. It is my understanding that techniques such as e-beam deposition and etching generally involve significantly higher fabrication costs compared to alternative methods like electrospinning. Given these findings, a critical evaluation of the water-floating-based nTP method is warranted to ascertain its continued cost-effectiveness. Subsequent to such an introduction, a new paragraph may commence with the phrase \"Among these methods, nTP...\".\nMiddle of Page 2: The authors attribute this adhesion primarily to van der Waals forces. However, given the inherently weak nature of van der Waals forces, it is unlikely that they will result in such pronounced adhesion effects. Consequently, the explanation provided for the bonding mechanism between the nanostructure and substrate is ambiguous and lacks sufficient scientific rigor. Additionally, the sentence “Subsequently, the suspended mesh floats on the water and can be easily transferred to curved surfaces, as shown in Fig. 1(a-ii)” may be misleading, as Fig. 1(a-ii) depicts the mesh floating on the water rather than being transferred onto a curved surface.\nBottom of Page 2: The statement “However, this method requires an additional electrospinning step” should be reconsidered. The primary limitation of the previous studies may lie not in the electrospinning step, which is analogous to plasma etching in nanopattern fabrication, but rather in the necessity of an adhesive layer.\nMiddle of Page 4: Since Fig. S3 schematically illustrates the process for fabricating the Au mesh via water-floating transfer, it should precede Figs. S1 and S2 in the presentation. The authors should also specify the materials comprising the square dot features—for example, what material are the dots composed of in the images where the width decreases with increasing etching time? In Fig. 2(b), although yellow bars are used to highlight the Au mesh, the original unmarked images should also be provided, or the yellow bars can be replaced with open rectangles or ovals for improved clarity. In Fig. 2(d), EDS images for Pt and Pd meshes appear less distinct than those for Au and Ni; the authors can explain this discrepancy.\nMiddle of Page 5: To validate the crack-free transfer of Au mesh via electrical resistance measurements, resistance should be plotted as a function of the radius of curvature of the lens, rather than Au mesh thickness, unlike Fig. 3(b).\nTop of Page 7: Although Video S2 provides a macro-level demonstration that no apparent defects are present on the leaf surface post-watering, Fig. S5 unveils microstructural defects such as fractures, distortions, and wrinkles within the gold nanostructure, thereby contradicting the authors' account. Furthermore, the article does not provide sufficient detail to ascertain whether the gold nanostructure is monolayer or multilayer, offering only a superficial description. Additionally, the authors should clarify the origin or attribution of the gray area overlying the yellow lines that represent the Au mesh.\nBottom of Page 7: The experiments previously discussed should be appropriately cited here.\nMiddle of Page 8: In Fig. 4(c), the region coated with the Au mesh is indistinct. The areas labeled “Mesh region” and “Raw surface” appear as dark and bright regions, respectively. However, the magnified image of the Au mesh on the right appears to correspond to the bright area at the bottom, which creates confusion. Additionally, Fig. 4(b) should be positioned closer to Fig. 4(c), rather than Fig. 4(d), to better illustrate their relationship. Instead of Fig. 4(a), it would be more informative to include images showing contact angle measurements on electrospun TPU fibers with varying water/ethanol volume ratios.\nTop of Page 10: In Fig. 5(f), the rationale behind connecting the data points with sine (or cosine) curves should be clarified. Are these curves derived from theoretical models, such as the polarization dependence of SERS intensity? Furthermore, it would be beneficial to compare these findings with previous literature reporting similarly structured SERS substrates [Ref. 10: Adv. Mater. 2016, 28, 8695], either here or on Page 13.\nTop of Page 11: The authors may cite relevant literature concerning pesticide detection using flexible SERS substrates [Anal. Methods 2023, 15, 1028; Adv. Photonics Res. 2024, 5, 2300291]. In this context, was the thiram residue on leaves and fruits reduced during the scooping transfer of the floating mesh on water as shown in Fig. 1(a-iii)?\nPages 11–12: The figure numbering for Fig. 6 in the main text is inconsistent with the labeling of its panels and should be revised for clarity.", "reviewer_2": "This manuscript describes a water-floating based nanotransfer printing technique inspired by hydrographic printing. This technique can transfer different materials onto different substrates, including both hydrophilic and hydrophobic surfaces. However, there are some major issues should be addressed before publishing.\n1. As mentioned, the WF-nTP technique is inspired by hydrographic printing, what is the difference between them? What is the advancement of the WF-nTP technique comparing to hydrographic printing? Comparing to using PVA as sacrificial layer in hydrographic printing, what is the advancement?\n2. The key step in this WF-nTP technique is making nanostructure floating on the water. But what kind of parameters are needed to achieve this? One parameter mentioned in the manuscript is the thickness. The lowest limit of thickness is 20 nm and why is that? Another obvious parameter is related to the structure. What kind of structures can be successfully floated on the water or what size of structures?\n3. One of the advantages of this WF-nTP technique is the conformability of the metal nanomesh. However, majority of the evidence are from SEM images. Is there any quantified data to prove this? Like signal to noise ratio? In other words, what are the benefits that the conformability will bring about?", "reviewer_3": "This study proposes a water-floatation-based nanotransfer printing technique (WF-nTP) for transferring nanostructures onto three-dimensional curved and hydrophobic surfaces, and demonstrates its potential applications in SERS and gas sensing. By modulating interfacial adhesion through plasma etching and utilizing water surface tension to achieve self-floating nanostructure transfer, the authors present a perspective that aims to overcome the limitations of traditional nTP techniques, which typically rely on adhesives or high-temperature processes. However, despite exploring a nanomanufacturing method, the study still shows significant shortcomings in technological innovation, experimental rigor, and practical application potential, making it difficult to meet the breakthrough expectations of Nature Communications. Below, I have listed some issues in this paper for the authors' reference, which will help facilitate subsequent revisions and submission to a more specialized journal.\n1. The core transfer mechanism of WF-nTP relies on plasma etching to weaken the interfacial adhesion, coupled with water surface tension to enable the floating and transfer of nanostructures. However, this principle has a significant overlap in physical mechanism with existing transfer technologies based on sacrificial layers (such as the PVA fiber dissolution method) or interfacial tension regulation. Although WF-nTP omits the sacrificial layer preparation step, its primary innovation lies more in process optimization rather than principle innovation.\n2. Why can the mesh conform to different curved surfaces? The authors did not provide quantitative data on the flexibility of the mesh itself (such as the bending radius limit), making it difficult to explain how it can adapt to high-curvature surfaces.\n3. The SEM image of the mesh on the fiber structure in Fig. 4d does not seem to be well bonded to the fiber structure, but rather lies flat on the fiber surface, lacking microscopic evidence of interfacial bonding.\n4. Single-point Raman testing cannot reflect the overall signal distribution. It is more convincing to use mapping testing to statistically average the signal.\n5. The simulation results of the 3-layer mesh differ in the 1 layer (Fig. 5(f)), and the possible reasons need to be further explained. For the FDTD simulation of Fig5c, the author only provides the electromagnetic field simulation of the vertical nanogap, which is inaccurate for the entire multi-layer mesh system, and the effect of horizontal stacking randomness on the entire electromagnetic field should be considered. In addition, after the Au mesh is bent, its vertical nanogap may not be 20 nm.\n6. The authors should provide the conversion process to the EU residue standard (μg/cm²) in the experimental details. Based on authors' mentioned information, it can be inferred that the author calculated 6.49 µg/cm² based on an area of 1 cm². However, during the SERS measurement, the laser spot diameter corresponding to the 50x objective lens is usually at the micron level, which is much smaller than the sample application area (1 cm²). Obviously, the result of 6.49 µg/cm² provided by the authors is incorrect and should be higher than the EU standard. In addition, the detection limit of existing SERS technology for thiram is generally as low as nM level. The results in the manuscript (1 mM for leaf and 100 μM for fruit) are not competitive enough in terms of sensitivity. If the authors can prepare a smaller grid structure, it may have more research value and practical significance.\n7. There are some problems in H2 sensing applications: the sensor response is too low; the gas response time (1000s) is far behind the Pd-based sensors reported in the literature (response time <100s), which makes it difficult to support its application potential; the selectivity of the contrast gas is small (combustible gas) and the contrast gas concentration is too low; it should be compared with pure Pd and literature materials."}, "author_response": "Dear reviewer:\nRe. Response to reviewer comments on “Versatile Water-floated Nanostructures for Three-\nDimensional Nanotransfer Printing” by Byung-Ho Kang, Ji-Hwan Ha, Yeongjae Kwon, Sohee Jeon,\nDonho Lee, Byeongmin Kang, Soon Hyoung Hwang, Junseong Ahn, Jun-Ho Jeong, and Inkyu Park.\nWe deeply appreciate the comments of the reviewer and have addressed them in the revised\nmanuscript. We have also incorporated significantly more reasoning, which has helped us improve the\npresentation.\nThe responses are colored in blue text and the changes in manuscript are highlighted in red text in the\nmanuscript for your understanding\nThe detailed response to the referee comments follows:\nReviewers' comments:\nReviewer #1 (Remarks to the Author):\nThis manuscript reports the fabrication of metallic mesh structures via a water-floating-based\nnanotransfer printing (nTP) technique. In this technique, the metallic mesh is floated on a water surface\nand subsequently transferred onto a target substrate using a scooping procedure. By modulating the\nsurface tension through the addition of ethanol, the metallic mesh can be effectively transferred even\nonto hydrophobic and topographically complex surfaces such as lotus leaves. The Au and Pd meshes\nexhibit functionality as flexible SERS substrates and hydrogen gas sensors, respectively. Although the\nreplicated PUA mold may not be reusable, the water-floating-based nanotransfer technique may offer\nadvantages in terms of cost-effectiveness, high throughput, time efficiency, and process reliability, while\ncircumventing toxic or substrate-damaging procedures. However, the article is not entirely satisfactory\nin terms of clarity, particularly concerning the clarity of responses to technical questions. Therefore, I\ncannot recommend the publication of this manuscript without addressing these concerns, which are\ndetailed below.\nResponse: We sincerely appreciate your thorough evaluation and constructive overall comments\nregarding our manuscript. In response to your feedback, we have carefully revised both the manuscript\nand the response letter, with particular emphasis on clarifying the technical explanations for the\nadhesion mechanism and addressing your specific concerns. We have clarified all previously ambiguous\npoints, expanded our technical rationale, and enhanced figure organization and referencing to ensure\nclarity and completeness.\nAll your comments have been thoroughly addressed either through revising, additional discussion, or\nimproved data presentation. We would be grateful if you could reconsider our manuscript for\npublication considering these substantial revisions.\nThank you very much for your time and valuable suggestions.\n[Comment 1] Bottom of Page 1: These fabrication strategies fall under the category of top-down\napproaches. The authors are encouraged to introduce bottom-up approaches for constructing two- and\nthree-dimensional nanostructures and compare them with top-down approaches in terms of their\nrespective advantages and limitations. It is my understanding that techniques such as e-beam deposition\nand etching generally involve significantly higher fabrication costs compared to alternative methods\nlike electrospinning. Given these findings, a critical evaluation of the water-floating-based nTP method\nis warranted to ascertain its continued cost-effectiveness. Subsequent to such an introduction, a new\nparagraph may commence with the phrase \"Among these methods, nTP...\".\nResponse: We thank the reviewer for this constructive comment. In response, we have added a new\nintroductory paragraph that briefly introduces bottom-up nanofabrication approaches such as chemical\nvapor deposition and molecular self-assembly and compares them with top-down strategies, including\nour nanotransfer printing (nTP) method. While bottom-up approaches are effective for synthesizing\nnanomaterials at the atomic or molecular level, they often require material- and substrate-specific\nprocessing conditions such as high vacuum pressure, high temperature, or toxic chemicals, which limit\ntheir flexibility for direct pattern transfer onto diverse substrates that are vulnerable to such conditions.\nBy contrast, top-down methods such as nTP enable the direct replication of pre-defined nanostructures\nonto a wide variety of target surfaces, regardless of substrate chemistry, geometry, or wettability.\nMoreover, nTP is particularly suitable for transferring nanopatterned materials onto substrates with high\nfidelity. This advantage is further enhanced in our water-floating-based nTP (WF-nTP) method, which\nachieves substrate-independent and adhesive-free transfer via a simple, single-step scooping process.\nWe also acknowledge the reviewer’s concern regarding fabrication costs. While e-beam evaporation\nand plasma etching may involve upfront equipment cost, these steps are standard in many existing\nfabrication facilities. Once the nano patterned Si master mold is prepared, the transfer step is extremely\nlow-cost, rapid, and energy-efficient than other existing techniques. Furthermore, transferring the gold\nmesh on the substrate through using electrospinning fiber also requires e-beam or thermal deposition\nfacilities in order to deposit the gold layer. Therefore, our proposed strategy does not require\nsignificantly higher costs than electrospinning-based approach.\nOriginal manuscript: Introduction (Page 1, line 31)\nThe rapidly advancing field of next-generation nanotechnology is gaining considerable attention as\nit seeks to implement nanostructures on various two-dimensional and three-dimensional (3D)\nsurfaces, expanding the range of applications in various areas, such as chemical 1, 2, 3 and physical\nsensors 4, 5, 6, metamaterials 7, optical devices 8, 9, and surface-enhanced Raman scattering (SERS) 10,\n11, 12 . Among these methods, nTP distinguishes itself through its cost-effectiveness, high throughput,\ntime efficiency, high spatial resolution, reliability, and ability to accommodate diverse materials and\nmorphologies 21.\nChanges in manuscript: Introduction (Page 1, line 31)\nThe rapidly advancing field of next-generation nanotechnology is gaining considerable attention as\nit seeks to implement nanostructures on various two-dimensional and three-dimensional (3D)\nsurfaces, expanding the range of applications in various areas, such as chemical 1, 2, 3 and physical\nsensors 4, 5, 6, metamaterials 7, optical devices 8, 9, and surface-enhanced Raman scattering (SERS) 10,\n11, 12. Conventional techniques have been extensively employed to fabricate nanostructures on a\nvariety of substrates. Bottom-up approaches, such as self-assembly 13, chemical vapor deposition\n(CVD) 14, atomic layer deposition (ALD) 15, are effective for synthesizing nanomaterials at the atomic\nor molecular level. However, they often require material- and substrate-specific processing\nconditions such as high vacuum pressure, high temperature, or toxic chemicals, which limit their\nflexibility for direct pattern transfer onto diverse substrates that are vulnerable to such conditions. By\ncontrast, top down approaches, including e-beam lithography 16, focused-ion beam lithography 17,\nnanoimprint lithography 18, and nanotransfer printing (nTP) 19, 20, enable the direct fabrication of pre-\ndefined nanostructures onto a wide variety of target surfaces. Among these methods, nTP\ndistinguishes itself through its cost-effectiveness, high throughput, high process speed, high spatial\nresolution, reliability, and ability to accommodate diverse materials and morphologies 21.\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 2] Middle of Page 2: The authors attribute this adhesion primarily to van der Waals forces.\nHowever, given the inherently weak nature of van der Waals forces, it is unlikely that they will result\nin such pronounced adhesion effects. Consequently, the explanation provided for the bonding\nmechanism between the nanostructure and substrate is ambiguous and lacks sufficient scientific rigor.\nAdditionally, the sentence “Subsequently, the suspended mesh floats on the water and can be easily\ntransferred to curved surfaces, as shown in Fig. 1(a-ii)” may be misleading, as Fig. 1(a-ii) depicts the\nmesh floating on the water rather than being transferred onto a curved surface.\nResponse: We appreciate the reviewer’s valuable comment regarding the attribution of adhesion\nprimarily to van der Waals forces, and we acknowledge that van der Waals interactions alone are\ntypically insufficient to account for the pronounced adhesion observed during the transfer of gold\nnanomesh onto hydrophilic substrates. We agree that the explanation benefits from clarification and a\nmore comprehensive perspective on the bonding mechanisms involved.\nIn the revised manuscript, we have strengthened our discussion of the sequential and synergistic\nmechanisms that govern adhesion in this system. Specifically, during the initial stages of transfer, when\nthere is still a thin water layer present between the nanomesh and the substrate, capillary forces\ngenerated by the formation of liquid menisci play a dominant role. As water evaporates, the curvature\nof the meniscus increases, leading to a significant rise in capillary pressure that pulls the nanomesh into\nintimate contact with the substrate based on Laplace equation [1]. This capillary-driven process is well\ndocumented to induce strong, short-range attractive forces [1, 2], which can temporarily result in\nadhesion strengths much higher than those achievable by van der Waals forces alone.\nAs the drying process concludes and the water eventually disappears, van der Waals forces become the\ndominant source of sustained adhesion between the gold nanomesh and the substrate. It is important to\nnote, however, that the effectiveness of van der Waals forces is markedly increased due to the minimized\nseparation distance achieved by the preceding capillary-driven contact. In other words, the capillary\naction serves to bring the nanomesh and substrate surfaces into exceedingly close proximity, thereby\nmaximizing the van der Waals interaction [1, 2]. This sequence of events is analogous to the well-known\n“stiction” phenomena encountered in MEMS devices, where capillary condensation during drying leads\nto persistent adhesion even after the liquid has fully evaporated [3-6].\nWe have incorporated additional references and revised the relevant sections in the manuscript to\nexplicitly emphasize this sequential, cooperative mechanism. Consequently, our revised explanation\nprovides a rigorous physical basis for the observed strong adhesion, grounded in the interplay between\ncapillary forces (dominant during drying) and van der Waals forces (sustaining the final state),\nparticularly in the context of hydrophilic substrates and nanostructured films.\nRepresentation of release problem in MEMS components due to capillary and van der Waals force\nduring wet etching (rinsing) process. (from [5])\nStiction phenomenon, (A) intended microstructure, (B) consequence of stiction. (from [6])\nWe hope this clarification satisfactorily addresses the reviewer’s concerns regarding the scientific rigor\nand completeness of our mechanistic explanation.\nOriginal manuscript: Introduction (Page 2, line 68)\nOnce the water dries, the mesh stably adheres onto the substrate through van der Waals forces. The\nversatility of water-floating nanotransfer printing (WF-nTP) has been demonstrated on various 3D\nsubstrates, such as curved optical lenses and plant leaves with micro/nanoscale roughness. The metal\nnanomesh conformed to these surfaces without defects.\nChanges in manuscript: Introduction (Page 2, line 68)\nOnce the water dries, the mesh stably adheres onto the substrate through van der Waals forces. The\nversatility of water-floating nanotransfer printing (WF-nTP) has been demonstrated on various 3D\nsubstrates, such as curved optical lenses and plant leaves with micro/nanoscale roughness. During\nthe drying process, the progressive evaporation of water reduces the size of the liquid meniscus\nformed between the gold nanomesh and the substrate. This reduction in meniscus size leads to an\nincrease in its curvature, thereby significantly enhancing the capillary forces that pull the mesh into\nintimate contact with the substrate and promote strong, short-range adhesion 26, 27, 28, 29. Once the\nwater has completely evaporated, the mesh remains stably adhered to the substrate through van der\nWaals forces, which are maximized by the close contact established during the capillary-driven\nprocess. In other words, the capillary action serves to bring the nanomesh and substrate surfaces into\nexceedingly close proximity, thereby maximizing the van der Waals interaction. The versatility of\nwater-floating nanotransfer printing (WF-nTP) has been demonstrated on various 3D substrates, such\nas curved optical lenses and plant leaves with micro/nanoscale roughness. The metal nanomesh\nconformed to these surfaces without defects.\nAlso, we agree that the sentence “Subsequently, the suspended mesh floats on the water and can be\neasily transferred to curved surfaces, as shown in Fig. 1(a-ii)” may be misleading. Therefore, we revise\nthe sentence as follows.\nOriginal manuscript: Introduction (Page 2, line 66)\nSubsequently, the suspended mesh floats on the water and can be easily transferred to curved\nsurfaces, as shown in Fig. 1(a-ii)\nChanges in manuscript: Introduction (Page 2, line 66)\nSubsequently, the suspended mesh floats on the water (Fig. 1(a-ii)) and can be easily transferred to\ncurved surfaces.\nReference\n[1] Tas, Niels, et al. \"Stiction in surface micromachining.\" Journal of Micromechanics and\nMicroengineering 6.4 (1996): 385.\n[2] Zhuang, Y. X., and A. Menon. \"On the stiction of MEMS materials.\" Tribology Letters 19.2 (2005):\n111-117.\n[3] Gupta, Vijay, et al. \"Recovery of stiction-failed MEMS structures using laser-induced stress waves.\"\nJournal of microelectromechanical systems 13.4 (2004): 696-700.\n[4] Rogers, James W., and Leslie M. Phinney. \"Process yields for laser repair of aged, stiction-failed,\nMEMS devices.\" Journal of microelectromechanical systems 10.2 (2002): 280-285.\n[5] Sethuramiah, A., and R. Kumar. \"Boundary lubrication mechanisms and modeling.\" Modeling of\nChemical Wear (2016): 69-104.\n[6] Ozevin, Didem. \"Microelectromechanical systems for assessing and monitoring civil\ninfrastructures.\" Sensor technologies for civil infrastructures. Woodhead Publishing, 2022. 237-272.\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 3] Bottom of Page 2: The statement “However, this method requires an additional\nelectrospinning step” should be reconsidered. The primary limitation of the previous studies may lie not\nin the electrospinning step, which is analogous to plasma etching in nanopattern fabrication, but rather\nin the necessity of an adhesive layer\nResponse: Thank you for your valuable comment. In our manuscript, our intention in stating “an\nadditional electrospinning step” was to emphasize the need for extra processing steps in previous\nmethods, rather than to suggest that electrospinning itself is fundamentally problematic. We agree that\nthe primary limitation in these prior techniques lies not in the electrospinning process itself, but rather\nin the requirement for an adhesive or sacrificial layer, which can complicate the transfer and affect\ndevice performance.\nUnlike those methods, our WF-nTP approach eliminates the need for sacrificial layers such as\nelectrospun fibers or PVA films. Compared to conventional hydrographic printing that relies on PVA\nsacrificial layers, our method allows the metal nanomesh to float directly on water without requiring\npre-dissolved PVA films, simplifying the process and avoiding potential residue contamination that can\nimpair electrical and surface properties. Moreover, our technique removes the need for chemical\ndissolution steps and enables repeated transfers without fresh sacrificial materials, reducing complexity\nand environmental impact. This simplification highlights the novelty and advantage of our approach.\nFollowing your valuable comment, we have revised the introduction part as you suggested.\nOriginal manuscript: Introduction (Page 4, line 91)\nMiyamoto et al. developed a simpler approach using water-soluble polyvinyl alcohol (PVA)\nelectrospun (ES) fibers as a sacrificial material, enabling the transfer of Au nanowires to various\nsurfaces, including human skin, by washing the PVA with water 31. However, this method requires\nan additional electrospinning step. By contrast, the WF-nTP technique eliminates the need for\nadhesive layers, toxic solvents, thermal energy, or sacrificial materials. The nanostructure can be\neasily transferred onto curved surfaces by simply scooping them in a water bath, making the process\nsimpler and more versatile.\nChanges in manuscript: Introduction (Page 4, line 91)\nMiyamoto et al. developed a simpler approach using water-soluble polyvinyl alcohol (PVA)\nelectrospun (ES) fibers as a sacrificial material, enabling the transfer of Au nanowires to various\nsurfaces, including human skin, by washing the PVA with water 31. However, this method requires\nan additional electrospinning step relies on sacrificial layers that may introduce residue and process\ncomplexity. By contrast, the WF-nTP technique eliminates the need for adhesive layers, toxic\nsolvents, thermal energy, or sacrificial materials, allowing the metal nanomesh to float directly on\nwater and be transferred via a simplified, residue-free process. Therefore, the nanostructure can be\neasily transferred onto curved surfaces by simply scooping them in a water bath, making the process\nsimpler and more versatile.\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 4] Middle of Page 4: Since Fig. S3 schematically illustrates the process for fabricating the\nAu mesh via water-floating transfer, it should precede Figs. S1 and S2 in the presentation. The authors\nshould also specify the materials comprising the square dot features—for example, what material are\nthe dots composed of in the images where the width decreases with increasing etching time? In Fig.\n2(b), although yellow bars are used to highlight the Au mesh, the original unmarked images should also\nbe provided, or the yellow bars can be replaced with open rectangles or ovals for improved clarity. In\nFig. 2(d), EDS images for Pt and Pd meshes appear less distinct than those for Au and Ni; the authors\ncan explain this discrepancy.\nResponse: We appreciate your valuable comments. As you suggested, we have reordered the figures\nfor improved clarity. Figs. S1, S2, and S3 have been renumbered as Figs. S2, S3, and S1, respectively.\nFurthermore, the square dots mentioned in the manuscript are composed of Au (gold) deposited on PUA.\nAfter the removal of the Au square dots, as shown in the revised Fig. S1(b), the gray-colored square\ndots no longer appear on the right side of Fig. 2(b-i). For better understanding, we have added gray\nopen rectangles in the figure to indicate the original position of the square dots. The region that\ndecreases in width upon plasma etching corresponds to the PUA, which is eliminated due to its plasma\nsensitivity as etching time increases.\nAdditionally, for improved clarity, the yellow bars in Fig. 2(b) have been replaced with orange open\nrectangles, as you suggested. In case of EDS image, previous mapping image appeared less distinct\ndue to short acquisition time during mapping. Finally, we have remeasured with longer times and\nupdated the EDS images for the Pt and Pd meshes in Fig. 2(d) to present clearer results.Original\nmanuscript: Results (Page 4, line 111)\nThe Au-deposited polyurethane acrylate (PUA) mold was first prepared, as shown in Fig. S1. A\nsquare-dot replica PUA mold was obtained from the square-mesh patterned master mold through a\nnanoimprinting process. Subsequently, Au-deposited the PUA mold was fabricated using e-beam\nevaporation. For the nanomesh to float on water as illustrated in Fig. 2a, Au mesh was first separated\nfrom the PUA mold through selective plasma etching. Before plasma etching, the square dots were\nremoved using a metal-independent nanotransfer printing technique developed by the authors’ group.\nThis process successfully removed the upper square dots from the mold, as shown in Fig. 2(b-i) and\nFig. S2. Subsequently, the optimal plasma etching time was determined by examining its effects on\nthe PUA mold. Notably, as shown in Fig. 2(b-ii to b-iv), the width of the square dot region decreases\nwith increasing etching time, reducing the adhesion force between the Au mesh and mold.\nChanges in manuscript: Results (Page 4, line 111)\nFabrication of the water floated Au nanomesh is illustrated in Fig. S1. The Au-deposited polyurethane\nacrylate (PUA) mold was first prepared, as shown in Fig. S1. A square-dot replica PUA mold was\nobtained from the square-mesh patterned master mold through a nanoimprinting process.\nSubsequently, Au-deposited the PUA mold was fabricated using e-beam evaporation. Fig. S2 shows\nthe photographic images on this process. For the nanomesh to float on water as illustrated in Fig. 2a,\nAu mesh was first separated from the PUA mold through selective plasma etching. Before plasma\netching, the square dots were removed using a metal-independent nanotransfer printing technique\ndeveloped by the authors’ group. This process successfully removed the upper square dots from the\nmold, as shown in Fig. 2(b-i) and Fig. S3. The detailed process is presented in Fig. S3. Subsequently,\nthe optimal plasma etching time was determined by examining its effects on the PUA mold. Notably,\nas shown in Fig. 2(b-ii to b-iv), the width of the square dot region of PUA decreases with increasing\netching time, reducing the adhesion force between the Au mesh and mold.\nOriginal Figure 2:\nFig. 2 Various morphological analyses of the floated nanostructure. a, Conceptual illustration of\nthe water-floated nanomesh. b, Cross-sectional images of the square mesh mold with Au (depicted\nin orange), showing the dot removing procedure (b-i) and the effects of different etching times (b-\nii to b-iv). ~\nRevised Figure 2\nFig. 2 Various morphological analyses of the floated nanostructure. a, Conceptual illustration of\nthe water-floated nanomesh. b, Cross-sectional images of the square dot and mesh mold with Au\n(depicted in gray- and orange-colored open rectangles), showing the dot removing procedure (b-i)\nand the effects of different etching times (b-ii to b-iv). ~\n[Comment 5] Middle of Page 5: To validate the crack-free transfer of Au mesh via electrical resistance\nmeasurements, resistance should be plotted as a function of the radius of curvature of the lens, rather\nthan Au mesh thickness, unlike Fig. 3(b).\nResponse: Thank you for your insightful comment. However, we believe there may be a\nmisunderstanding regarding the purpose and interpretation of Fig. 3(b). The aim of this figure is to\ndemonstrate that the electrical resistance of the transferred Au mesh remains consistent for different\nradii of curvature (R₆, R₁₄, R₁₆, R₂₀) at each given Au thickness. In our experiment, we transferred the\nAu mesh onto lenses with varying curvatures and measured the resistance for each case as a function of\nAu thickness. The key point is, regardless of the lens curvature, the measured electrical resistance values\nwere almost identical when the Au thickness was the same.\nThis result clearly indicates that the Au mesh can be conformally and crack-free transferred onto\nsurfaces with different curvatures, as any cracking or discontinuity would induce a significant deviation\nor increase in electrical resistance among the samples. If any cracks or damage occurred during the\ntransfer to higher-curvature lenses, the electrical resistance would increase for those samples. However,\nour data shows that the resistance remains nearly unchanged across all curvature conditions,\nsubstantiating the crack-free and reliable transfer of Au mesh by our method.\nTherefore, while plotting resistance as a function of radius of curvature could be informative, our\nintended demonstration is that the electrical resistance does not change with curvature at a fixed Au\nthickness. Thus, Fig. 3(b) is the appropriate representation to validate the crack-free transfer\nperformance from the viewpoint of electrical continuity and performance on various curvatures.\nHowever, as you suggested, the resistance as a function of the lens radius of curvature is plotted in Fig.\nS4 for clearer interpretation. We hope this clarifies the experimental rationale and interpretation.\nFig S4. Electrical resistance of transferred metal meshes as a function of lens radius of curvature for different\nAu thickness (20, 40, 80, and 100nm). The results demonstrate stable electrical connection and low resistance\nvariation across various curvatures, indicating crack-free and reliable transfer performance. Additionally, for Au\nof the same thickness, the electrical resistance remains identical despite changes in the radius of curvature,\nfurther confirming consistent performance across different curvatures.\nOriginal manuscript: Results (Page 6, line 156)\nAu meshes with thicknesses of 20, 40, 80, and 100 nm were transferred onto four lenses with different\nradii of curvature, and the resistance was measured by placing the probe in contact with the edge of\neach mesh, as shown in Fig. 3(b).\nChanges in manuscript: Results (Page 6, line 156)\nAu meshes with thicknesses of 20, 40, 80, and 100 nm were transferred onto four lenses with different\nradii of curvature, and the resistance was measured by placing the probe in contact with the edge of\neach mesh, as shown in Fig. 3(b) and Fig. S4.\nChanges in Figure: The attached figure was added to the supplementary information. (Fig. S4)\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 6] Top of Page 7: Although Video S2 provides a macro-level demonstration that no apparent\ndefects are present on the leaf surface post-watering, Fig. S5 unveils microstructural defects such as\nfractures, distortions, and wrinkles within the gold nanostructure, thereby contradicting the authors'\naccount. Furthermore, the article does not provide sufficient detail to ascertain whether the gold\nnanostructure is monolayer or multilayer, offering only a superficial description. Additionally, the\nauthors should clarify the origin or attribution of the gray area overlying the yellow lines that represent\nthe Au mesh.\nResponse: Thank you very much for your constructive comments regarding Fig. S5 and the discussion\nof microstructural defects in the Au nanomesh.\nTo address your concerns, we have replaced the previously used SEM images with new images acquired\nat higher resolution and lower magnification. These updated micrographs provide a clearer and more\ncomprehensive visualization of the entire mesh region. In particular, the improved images more\naccurately show the absence of any significant defects, such as large holes or severe fractures, after the\nwater shower test. We believe these enhanced figures resolve the ambiguity that may have arisen from\nthe limitations of our previous lower-quality images.\nWe would also like to emphasize that, as is common in the fabrication and transfer of ultrathin\nnanostructures onto natural surfaces, it is not possible to guarantee the complete absence of all defects.\nIn our manuscript, we have intentionally and transparently used the term \"no significant defects\"\nrather than \"no defects,\" in order to acknowledge the possibility of occasional minor imperfections.\nNevertheless, our results clearly demonstrate that, even after exposure to relatively strong water\npressure such as from a shower head, the Au nanomesh remains firmly attached and retains its structural\nintegrity without substantial damage or electrical failure. We believe this robustness is highly relevant,\nas it showcases the potential of our approach for applications such as plant-based monitoring systems,\nwhere resistance to rain or splashing water is important.\nWe have also revised the manuscript and relevant figure captions to clearly state that the Au nanomesh\nconsists of a single layer (\"1-layer mesh\"). To avoid any ambiguity, we have added this description both\nin the text and in the figure annotations.\nAdditionally, regarding the gray area overlying the yellow lines representing the Au mesh, we have\nclarified that the yellow lines are used to visually indicate the location of the high-magnification SEM\nimage of the 1-layer mesh on the leaf.\nThank you again for your helpful suggestions, which have improved the clarity and completeness of\nour manuscript.\nOriginal manuscript: Result (Page 8, line 204)\nTo confirm this result at the microscopic level, SEM analysis was performed on the mesh before and\nafter showering, as shown in Fig. S5. Notably, no significant defects or damage were observed after\nshowering, indicating that the mesh was robust and firmly adhered to the leaf. These results confirm\nthat the WF-nTP method is particularly advantageous for transferring various functional\nnanopatterned metals onto rough surfaces.\nChanges in manuscript: Result (Page 8, line 204)\nTo confirm this result at the microscopic level, SEM analysis was performed on the 1-layer mesh\nbefore and after showering, as shown in Fig. S9. Notably, no significant defects or damage such as\nlarge holes, fractures, or distortions were observed after showering, indicating that the mesh was\nrobust and firmly adhered to the leaf. While minor defects typical in ultrathin nanostructure on rough\nnatural surfaces may exist, these did not affect the overall structural integrity or electrical\nperformance of the mesh. These results confirm that the WF-nTP method is particularly\nadvantageous for transferring various functional nanopatterned metals onto rough surfaces,\ndemonstrating excellent mechanical stability even under strong water exposure.\nOriginal Figure S9:\nFig. S9 Stability of the nanomesh on a leaf before and after showering. The stability of the nanomesh on a leaf\nbefore and after showering was performed. The mesh remains intact and well-adhered both visually and\nmicroscopically, as shown in the photographic images taken before and after the shower. SEM analysis further\nconfirms the mesh’s stability, revealing no significant defects or damage to the structure at the micro-scale, even\nafter pouring water.\nRevised Figure S9:\nFig. S9 Stability of the 1-layer nanomesh on a leaf before and after showering. The stability of the 1-layer\nnanomesh on a leaf before and after showering was performed. The mesh remains intact and well-adhered both\nvisually and microscopically, as shown in the photographic images taken before and after the shower. SEM\nanalysis further confirms the mesh’s stability, revealing no significant defects or damage to the structure at the\nmicro-scale, even after pouring water (Yellow line reveals the Au mesh).\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 7] Bottom of Page 7: The experiments previously discussed should be appropriately cited\nhere.\nResponse: Thank you for your valuable comments. As we understand, we have cited the paper\nregarding the surface tension of the water/ethanol mixture in the sentence: “However, when the ethanol\nvolume fraction exceeded 30%, the Au mesh could no longer float on the surface of the solution owing\nto the excessively low surface tension [reference].” If this interpretation is not what you intended, please\nkindly let us know.\nOriginal manuscript: Result (Page 10, line 237)\nHowever, when the ethanol volume fraction exceeded 30%, the Au mesh could no longer float on the\nsurface of the solution owing to the excessively low surface tension.\nChanges in manuscript: Result (Page 10, line 237)\nHowever, when the ethanol volume fraction exceeded 30%, the Au mesh could no longer float on the\nsurface of the solution owing to the excessively low surface tension 34.\nRef 34 (previous Ref. 25): Journal of Molecular Liquids 262, 255-260 (2018)\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 8] Middle of Page 8: In Fig. 4(c), the region coated with the Au mesh is indistinct. The areas\nlabeled “Mesh region” and “Raw surface” appear as dark and bright regions, respectively. However, the\nmagnified image of the Au mesh on the right appears to correspond to the bright area at the bottom,\nwhich creates confusion. Additionally, Fig. 4(b) should be positioned closer to Fig. 4(c), rather than Fig.\n4(d), to better illustrate their relationship. Instead of Fig. 4(a), it would be more informative to include\nimages showing contact angle measurements on electrospun TPU fibers with varying water/ethanol\nvolume ratios.\nResponse: Thank you for your helpful comments regarding Fig. 4(c) and the clarity of the regions\nlabeled “Mesh region” and “Raw surface.”\nIn this experiment, the Au mesh was transferred onto the backside of the plant leaf to clearly show the\nboundary between the region covered with the Au mesh (“Mesh region”) and the original surface (“Raw\nsurface”). The intention was to visually distinguish these two areas by presenting the interface in the\nfigure. To provide more clarity, we have included a magnified SEM image of the Au mesh region, which\nhas been added to the right side of the figure. In SEM imaging, areas with the Au mesh appear brighter\nbecause gold is highly conductive, resulting in less charging and therefore increased image brightness.\nIn contrast, the “Raw surface” (uncoated region) appears comparatively dark without conductive\ncoating. This difference in brightness makes it easier to visually distinguish the two regions in the SEM\nimages. However, the area labeled as the 'Mesh region' appears unintentionally dark due to a different\nfocal distance. Therefore, the yellow box highlights the mesh region.\nIn response to your comments, we have reorganized the figures to better clarify the relationships among\nthe data. Specifically, the previous Fig. 4(a) has been moved to the supplementary section as Fig. S10.\nWe have also repositioned the former Fig. 4(b) and Fig. 4(c) to become the new Fig. 4(a) and Fig. 4(b),\nrespectively. This revised order places the related data in closer proximity, allowing for a more logical\nand intuitive presentation. Furthermore, as you suggested, we have now included a new image as Fig.\n4(c) that shows water contact angle measurements on electrospun TPU fibers with various water/ethanol\nvolume ratios. We believe that this addition provides clearer and more relevant information about the\ninfluence of solution composition on the wetting behavior of the electrospun fibers.\nAll corresponding figure captions have been updated accordingly in the revised manuscript. Thank you\nagain for your valuable feedback, which has allowed us to enhance both the scientific content and\nreadability of our work.\nOriginal manuscript: Result (Page 10, line 245)\nTo further verify the versatility of the substrate, ES TPU fibers were fabricated and used as another\nexample of a hydrophobic surface 23. Fig. 4(d) shows the successful transfer of the Au mesh onto the\nfibers.\nChanges in manuscript: Result (Page 10, line 245)\nTo further verify the versatility of the substrate, ES TPU fibers were fabricated and used as another\nexample of a hydrophobic surface 23. As shown in Fig. 4(c), the contact angle variation with changing\nethanol-to-water volume ratios exhibited a similar trend for the ES TPU fibers. Fig. 4(d) shows the\nsuccessful transfer of the Au mesh onto the fibers.\nOriginal Figure 4:\nFig. 4 Transfer to hydrophobic surfaces and morphological analysis. a, Comparison of water\ncontact angles on slide glass, the front side, and the back side of the leaf. b, Contact angle\nmeasurements on the back side of the leaf using different volume ratios of DI water and ethanol.\nc, SEM images of the Au mesh on the back side of the leaf, showing conformal contact with the\nrough surface. d, SEM images of the Au mesh on hydrophobic electrospun TPU fibers. e, Contact\nangle measurements on the lotus leaf using different volume ratios of DI water and ethanol. As\nethanol content increases, the contact angle decreases, indicating improved wetting properties\non the lotus leaf surface. f, SEM images of the raw lotus surface and the transferred Au mesh on\nthe lotus leaf.\nRevised Figure 4:\nFig. 4 Transfer to hydrophobic surfaces and morphological analysis. a, Contact angle\nmeasurements on the back side of the Nandina domestica leaf using different volume ratios of DI\nwater and ethanol. b, SEM images of the Au mesh on the back side of the leaf, showing conformal\ncontact with the rough surface. c, Contact angle measurements on the electrospun TPU fiber using\ndifferent volume ratios of DI water and ethanol. d, SEM images of the Au mesh on hydrophobic\nelectrospun TPU fibers. e, Contact angle measurements on the lotus leaf using different volume\nratios of DI water and ethanol. As ethanol content increases, the contact angle decreases,\nindicating improved wetting properties on the lotus leaf surface. f, SEM images of the raw lotus\nsurface and the transferred Au mesh on the lotus leaf.\nUpdated Figure S10:\nFig. S10. Water contact angle measurements on slide glass and the front and back sides of the Nandina\ndomestica leaf. Comparison of water contact angles measured on the three substrates. Both the slide glass\nand the front side of the leaf exhibit hydrophilic behavior, while the back side of the leaf exhibits hydrophobic\nbehavior.\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 9] Top of Page 10: In Fig. 5(f), the rationale behind connecting the data points with sine (or\ncosine) curves should be clarified. Are these curves derived from theoretical models, such as the\npolarization dependence of SERS intensity? Furthermore, it would be beneficial to compare these\nfindings with previous literature reporting similarly structured SERS substrates [Ref. 10: Adv. Mater.\n2016, 28, 8695], either here or on Page 13.\nResponse: Thank you very much for your thoughtful comment regarding the fitting curves in Fig. 5(f).\nWe would like to clarify that the curves connecting the data points (both for the simulated enhancement\nfactor and the experimental SERS intensity) are not based on a specific theoretical model such as the\npolarization dependence of SERS or any physical equation. Instead, we applied a polynomial fitting\nsolely to illustrate the trend in the observed data more clearly. The fitted curves are intended as a visual\nguide to help interpret how both the simulated (black squares) and experimental (red squares) values\nchange as a function of the number of stacked layers. As the number of Au mesh layers increases, both\nthe simulation results (maximum E-field enhancement) and the experimental SERS intensities increase,\nreaching a maximum at seven layers, and then decrease beyond this point. The polynomial fitting was\napplied to emphasize this consistent trend rather than to suggest any direct theoretical relationship.\nOriginal manuscript: In figure 5 caption\nf, Maximum E-field enhancement (E/E ≥ 1) of the multi-layered structure and the relative SERS\n0\nsignal intensity at ~1510 cm⁻¹ for 10⁻⁶ M R6G with curve fitting.\nChanges in manuscript: In figure 5 caption\nf, Maximum E-field enhancement (E/E ≥ 1) of the multi-layered structure and the relative SERS\n0\nsignal intensity at ~1510 cm⁻¹ for 10⁻⁶ M R6G with curve polynomial fitting.\nThis observed behavior is consistent with what has been reported in Ref. 10 (Adv. Mater. 2016, 28,\n8695). In that reference, the authors found that the SERS enhancement increased with the number of\nstacked Au nanowire layers up to five and then decreased for higher stacking numbers as described in\nthe following: \"the maximum e-field enhancement increases up to five layers of stacking. However, for\neight and ten stacking layers, the e-field enhancement is smaller than that for five ... (this is due to)\nthe interference of waves propagating back and forth across the stacking layers ... it may not be\nstraightforward to directly correlate the measured SERS intensity with the maximum field enhancement\nratio of a local point because the total Raman intensity is the integrated sum of the contributions from\nvarious hot spots. However, considering that the (experimentally measured) minimum number of Au\nnanowire layers providing the highest SERS intensity is five, ... these results suggest that the hot spots\nformed at the junctions between the topmost and the second-layer nanowires play the most significant\nrole.\"\nFrom Ref 10: Adv. Mater. 2016, 28, 8695 (Figure 3)\nAlthough there is a difference in the optimal stacking number due to differences in the structural design\n(our work uses a mesh structure while Ref. 10 used stacked nanowires), the key phenomenon remains\nthe same: There exists an optimal number of stacking layers that maximizes SERS enhancement,\nbeyond which further stacking results in a decrease in enhancement, as shown in ref 10, figure 3(g).\nThis is attributed to effects such as interference and changes in hot spot density/distribution within the\n3D structure. Our findings are reinforced and are in good agreement with these prior results, further\nconfirming that careful design of the stacking architecture is necessary to achieve optimal SERS\nperformance.\nWe have revised the manuscript to clarify the rationale behind the choice of polynomial fitting for trend\nvisualization and added a discussion highlighting the consistency with previous literature as suggested.\nThank you again for your insightful feedback, which helped us improve the clarity and context of our\nresults.\nOriginal manuscript: Discussion (Page 15, line 378)\nFirst, a SERS mesh was developed using a multilayer stacking procedure. The optimal number of\nlayers for achieving the highest e-field enhancement was determined through FDTD simulations and\nconfirmed by experimental results. The seven-layer mesh provided the best conditions for SERS and\nwas successfully applied for pesticide detection on fruits and leaves.\nChanges in manuscript: Discussion (Page 15, line 378)\nFirst, a SERS mesh was developed using a multilayer stacking procedure. The optimal number of\nlayers for achieving the highest e-field enhancement was determined through FDTD simulations and\nconfirmed by experimental results. The seven-layer mesh provided the best conditions for SERS and\nwas successfully applied for pesticide detection on fruits and leaves. This trend closely matches\nprevious results reported for nanowire-based SERS substrates 10, where optimal enhancement was\nalso achieved at a moderate stacking number. While the specific optimal layer differs due to structural\ndifferences, both studies demonstrate that there exists an optimal stacking condition maximizing\nSERS performance.\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 10] Top of Page 11: The authors may cite relevant literature concerning pesticide detection\nusing flexible SERS substrates [Anal. Methods 2023, 15, 1028; Adv. Photonics Res. 2024, 5, 2300291].\nIn this context, was the thiram residue on leaves and fruits reduced during the scooping transfer of the\nfloating mesh on water as shown in Fig. 1(a-iii)?\nResponse: Thank you for your valuable comment and the suggested references regarding pesticide\ndetection using flexible SERS substrates.\nRegarding the concern about potential reduction of thiram residue during the water floating transfer\nprocess shown in Fig. 1(a-iii), we would like to clarify the following. In our method, the Au mesh is\ntransferred onto the substrate (e.g., fruit or leaf) by scooping up the floating multilayer mesh from water.\nThe process involves brief contact with water but is not equivalent to washing or rinsing the sample.\nTherefore, we expect that the thiram residue present on the surface prior to transfer remains largely\nintact after the transfer process, as the water contact time during scooping is brief and does not constitute\na full washing step.\nTo demonstrate proof-of-concept, our experiments involved first transferring the 7-layer mesh onto the\nfruit or leaf, followed by applying thiram solutions of various concentrations on top of the mesh by drop\ncasting. This approach, similar to the methods used in the references you provided [Anal. Methods 2023,\n15, 1028; Adv. Photonics Res. 2024, 5, 2300291], was designed to validate the SERS detection\ncapability at different pesticide levels and does not represent a direct measurement of naturally residual\nthiram after transfer. Moreover, drop casting was employed to enable controlled concentration analysis\nand to confirm the SERS performance of the transferred mesh under well-defined conditions.\nNevertheless, we acknowledge that a detailed study assessing the effect of the water floating transfer\non pesticide residue retention in real agricultural samples is crucial and is part of our future research\nplans. Meanwhile, the references you provided support the feasibility of flexible SERS substrates for\nnon-destructive pesticide detection, aligning well with our approach.\nWe have cited the suggested literature in the revised manuscript to clarify these points.\nOriginal manuscript: Result (Page 13, line 317)\nThis technique enables direct and rapid printing without damaging the surface, enabling the simple\nand nondestructive detection of pesticides on leaves and fruits using SERS 33, 34, 35\nChanges in manuscript: Result (Page 13, line 317)\nThis technique enables direct and rapid printing without damaging the surface, enabling the simple\nand nondestructive detection of pesticides on leaves and fruits using SERS 42, 43, 44, 45, 46\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 11] Pages 11–12: The figure numbering for Fig. 6 in the main text is inconsistent with the\nlabeling of its panels and should be revised for clarity.\nResponse: Thank you for pointing out the inconsistency in the figure numbering of Fig. 6 and its panels\nin the main text. We apologize for any confusion this may have caused. We have carefully revised the\nmanuscript to correctly match the figure references with their respective panels. Specifically, we have\nadded detailed descriptions of Fig. 6(a) and Fig. 6(b) in the main text to complement the existing\ndiscussion and updated the figure captions to accurately correspond to each panel. These changes\nimprove the clarity and coherence of the presentation. We appreciate your valuable feedback, which\nhelped enhance the manuscript quality.\nOriginal manuscript: Result (Page 13, line 347)\nWhen Pd is exposed to hydrogen gas, it undergoes a reversible transformation into palladium hydride\n(PdHx), increasing electrical resistance 3. This change in resistance provides a straightforward\nmechanism for detecting hydrogen gas. In this study, the relative change in the sensor resistance was\ntested for hydrogen gas concentrations ranging from 0.25% to 1%.\nChanges in manuscript: Result (Page 13, line 347)\nWhen Pd is exposed to hydrogen gas, it undergoes a reversible transformation into palladium hydride\n(PdHx), increasing electrical resistance 3. This change in resistance provides a straightforward\nmechanism for detecting hydrogen gas. Fig. 6(a) schematically illustrates the structure of the Pd-\nbased hydrogen gas sensor formed on electrospun fibers, showing how the mesh interacts with\nincoming hydrogen molecules. Fig. 6(b) presents a photographic image of the sensor placed inside\nthe gas-testing chamber along with a corresponding SEM image, confirming the morphology and\nintegration of the Pd mesh with the fiber substrate. In this study, the relative change in the sensor\nresistance was tested for hydrogen gas concentrations ranging from 0.25% to 1%.\nReviewer #2 (Remarks to the Author):\nThis manuscript describes a water-floating based nanotransfer printing technique inspired by\nhydrographic printing. This technique can transfer different materials onto different substrates,\nincluding both hydrophilic and hydrophobic surfaces. However, there are some major issues should be\naddressed before publishing.\nResponse: Thank you for your careful review and valuable comments regarding our manuscript. In\nresponse to your suggestions, we have substantially revised the manuscript to address the comments.\nSpecifically, we have now included a clear comparison between our water-floating nanotransfer printing\n(WF-nTP) technique and conventional hydrographic printing methods, highlighting their fundamental\ndifferences and the unique advantages of WF-nTP. Additionally, we have provided detailed process\nparameters for the WF-nTP method to enhance reproducibility and transparency. Further, following\nyour advice, we conducted additional analyses on the conformability of the transferred nanomesh and\nincorporated these results in the revised manuscript.\nWe have carefully considered all of your comments, and we would be grateful if you could review our\nimproved manuscript. Thank you for your constructive feedback.\n[Comment 1] As mentioned, the WF-nTP technique is inspired by hydrographic printing, what is the\ndifference between them? What is the advancement of the WF-nTP technique comparing to\nhydrographic printing? Comparing to using PVA as sacrificial layer in hydrographic printing, what is\nthe advancement?\nResponse: Thank you for your insightful question regarding the differences and advancements of our\nWF-nTP technique compared to hydrographic printing.\nWhile our WF-nTP method was indeed inspired by hydrographic printing, there are several fundamental\ndifferences and significant advancements that distinguish our approach.\nTraditional hydrographic printing is limited to macro-scale patterns (typically decorative designs like\ncamouflage, marble, or wood grain patterns) printed on PVA films. Our WF-nTP technique enables the\ntransfer of nanoscale patterns and structures, which represents a significant advancement in resolution\ncapability. This nanoscale transfer capability opens applications in electronics, sensors, and precision\ndevices that are not achievable with conventional hydrographic printing.\nCompared to conventional hydrographic printing that relies on PVA sacrificial layers, our WF-nTP\nmethod offers several significant advantages. Our approach allows the Au nanomesh to float directly\non water without requiring a pre-dissolved PVA film, which simplifies the overall process and\neliminates potential residue issues that can affect the final product quality. Traditional hydrographic\nprinting often suffers from PVA residue contamination, where incomplete dissolution of the PVA film\ncan leave polymer residues on the transferred surface, potentially affecting the electrical properties and\nsurface quality of functional devices. Additionally, traditional hydrographic printing requires chemical\nactivators to dissolve the PVA film and separate the ink from the carrier, whereas our method eliminates\nthis chemical dissolution step entirely, making it more environmentally friendly and reducing process\ncomplexity. Furthermore, our water-based transfer process can be repeated multiple times without the\nneed for fresh sacrificial materials.\nOur WF-nTP technique expands the application scope significantly beyond the primarily decorative\npurposes of traditional hydrographic printing. While hydrographic printing is mainly used for aesthetic\napplications with repeatable macro-scale patterns on consumer goods, our method enables the\nfabrication of functional devices and precision instruments. The nanoscale pattern achieved through our\ntechnique allows for applications in advanced electronics and high-performance sensors that demand\nprecise pattern placement and structural fidelity, representing a paradigm shift from decorative to\nfunctional nanofabrication.\nIn summary, while both methods utilize water-based transfer principles, our WF-nTP technique\nrepresents a significant advancement in terms of resolution, precision, process control, and application\nversatility, particularly enabling nanoscale pattern transfer that was previously unachievable with\ntraditional hydrographic printing methods. We appreciate your thoughtful questions, which have\nallowed us to clarify these important distinctions and demonstrate the unique contributions of our work\nto the field of nanoscale pattern transfer. Following these comparisons, we have revised the introduction\npart of our manuscript.\nOriginal manuscript: Introduction (Page 4, line 84)\nThe proposed WF-nTP technique offers significant advantages, particularly for transferring materials\nonto curved surfaces. For comparison, the metal-independent nTP method proposed by Hwang et al.\nuses a self-assembled monolayer (SAM) layer and requires covalent bonding with an adhesive\ncoating at temperatures of at least 150 °C to transfer metals onto flat and curved surfaces 30.\nChanges in manuscript: Introduction (Page 4, line 84)\nThe proposed WF-nTP technique offers significant advantages, particularly for transferring nano-\nscale materials onto curved surfaces. Unlike conventional hydrographic printing, which is restricted\nto macro-scale decorative patterns on water-soluble films such as PVA, our WF-nTP method enables\nthe transfer of high-resolution nanoscale structures directly onto various substrates. This\nadvancement eliminates the need for sacrificial PVA layers and chemical activators, significantly\nreducing process complexity and the risk of polymer residue contamination. For further comparison,\nthe metal-independent nTP method proposed by Hwang et al. uses a self-assembled monolayer\n(SAM) layer and requires covalent bonding with an adhesive coating at temperatures of at least\n150 °C to transfer metals onto flat and curved surfaces 30.\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 2] The key step in this WF-nTP technique is making nanostructure floating on the water.\nBut what kind of parameters are needed to achieve this? One parameter mentioned in the manuscript is\nthe thickness. The lowest limit of thickness is 20 nm and why is that? Another obvious parameter is\nrelated to the structure. What kind of structures can be successfully floated on the water or what size of\nstructures?\nResponse: We appreciate the reviewer’s insightful question regarding the critical parameters necessary\nfor successful water-floating nanotransfer printing (WF-nTP). As the reviewer correctly pointed out,\nthe ability of nanostructures to float on water is central to our technique. Based on our experiments and\nprocess development, several key parameters must be optimized to enable stable floating and effective\ntransfer: plasma etching time, material properties, nanostructure geometry, liquid surface tension, and\nfilm thickness.\nPlasma etching time: As shown in Fig. 2(b-ii), a short plasma etching duration (e.g., 5 minutes) can\npartially weaken adhesion between the nanostructure and the PUA mold, causing the metal film to\nsuspend but not fully detach. For complete separation, a sufficiently long plasma exposure (~20 minutes)\nis required to minimize the interfacial adhesion, enabling the nanostructure to float off the mold. This\nextended treatment time is therefore essential for floating on the water, particularly when using\nrelatively rigid metallic meshes.\nOriginal manuscript: Result (Page 5, line 122)\nWhen the etching time exceeds 5 min, the Au mesh begins to suspend, with the mold fully collapsing\nafter 20 min. This process enables effective detachment of the Au mesh from the mold, as the\nadhesion force between them is nearly completely eliminated, weakening F .\nmold\nChanges in manuscript: Result (Page 5, line 122)\nWhen the etching time exceeds 5 min, the Au mesh begins to suspend, with the mold fully collapsing\nafter 20 min. Therefore, an optimal etching time of 20min This process enables effective detachment\nof the Au mesh from the mold, as the adhesion force between them is nearly completely eliminated,\nweakening F .\nmold\nMaterial properties: Our process employs a mixed CF₄ and O₂ plasma. Under these conditions, metals\nvulnerable to oxidation, such as silver, form surface oxides during etching, which reduce ductility and\ncompromise the mechanical integrity of the thin metal films. Oxidized silver films tend to become\nbrittle and fail to float on the water. In addition, excessive plasma exposure may physically etch or\ndelaminate fragile metal films along with the polymer mold. For these reasons, our current process is\nlimited to non-oxidizing metals like gold, palladium, platinum, and nickel. Exploring compatibility with\noxidizable materials is reserved for future work.\nOriginal manuscript: Result (Page 6, line 134)\nFig. 2(e) shows the energy-dispersive spectroscopy (EDS) mapping of various materials and mesh\nstructures, highlighting the diversity of the materials and mesh configurations. Notably, various\nmetals, such as Ni, Pt, and Pd, along with different mesh patterns, such as holes and cross-dots, can\nalso float on water and be transferred onto substrates.\nChanges in manuscript: Result (Page 6, line 134)\nFig. 2(e) shows the energy-dispersive spectroscopy (EDS) mapping of various materials and mesh\nstructures, highlighting the diversity of the materials and mesh configurations. Given that the WF-\nnTP process requires a plasma etching step, the choice of metals is limited to those resistant to\noxidation. Notably, various oxidation-resistant metals, such as Ni, Pt, and Pd, along with different\nmesh patterns, such as holes and cross-dots, can also float on water and be transferred onto substrates.\nNanostructure geometry: For successful and stable floating, the nanostructure must be laterally\ninterconnected. Mesh-type geometries (e.g., square mesh, hole arrays, cross-dot grids), shown in Fig.\n2(e), maintain mechanical integrity on the water surface and prevent uncontrolled drifting. Conversely,\ndisconnected patterns such as isolated dots or lines are prone to instability and random drifting on the\nwater.\nOriginal manuscript: Result (Page 6, line 136)\nNotably, various metals, such as Ni, Pt, and Pd, along with different mesh patterns, such as holes and\ncross-dots, can also float on water and be transferred onto substrates.\nChanges in manuscript: Result (Page 6, line 136)\nNotably, various oxidation-resistant metals, such as Ni, Pt, and Pd, along with different mesh patterns,\nsuch as holes and cross-dots, can also float on water and be transferred onto substrates. For successful\nand stable floating, the nanostructure must be laterally interconnected. Mesh-type geometries such\nas square mesh, hole arrays, cross-dot grids) maintain mechanical integrity on the water surface and\nprevent uncontrolled drifting.\nSurface tension of the water bath: As demonstrated in Fig. 4, floating is strongly influenced by the\nliquid’s surface tension. We find that a minimum surface tension of approximately 42.9 mN/m (@ water:\nethanol=80:20(v/v%)) is necessary for successful separation and floating. If the surface tension is too\nlow, even a sufficiently etched nanostructure will hardly detach cleanly from the mold. This highlights\nthe importance of tuning fluid surface properties in combination.\nOriginal manuscript: Result (Page 10, line 241)\nThe optimal liquid medium composition for hydrophobic surfaces was determined to be an 80/20\n(v/v) water/ethanol mixture.\nChanges in manuscript: Result (Page 10, line 241)\nThe optimal liquid medium composition for hydrophobic surfaces was determined to be an 80/20\n(v/v) water/ethanol mixture, exhibiting a surface tension of approximately 42.9mN/m 34.\nFilm thickness: Experimentally, the minimum floating thickness achieved was 20 nm. Films thinner\nthan 20 nm particularly near 10 nm exhibit severe embrittlement due to reduced grain size, limited\nplastic deformation, and increased defect density. Previous study on the mechanical properties of nano\nscaled thick gold films indicates that thickness‐dependent embrittlement arises because thinner films\nhave smaller grain structures and fewer mechanisms to dissipate deformation energy [1]. Grain‐\nboundary strengthening and defect concentration intensify as the metal layer thins, leaving insufficient\nplasticity. As a result, 10 nm Au films having even finer grains and minimal capacity for dislocation\nmotion are expected to fracture with high crack density and negligible ductility. In contrast, 20 nm films\nretain sufficient ductility for deformation during floating and transfer. Therefore, 20 nm represents the\nexperimental lower limit; films thinner than this are structurally too fragile to survive the floating\nprocess.\nOriginal manuscript: Result (Page 5, line 127)\nThe minimum thickness required for the mesh to stably float on water is 20 nm, allowing the ultrathin\nnanomesh to float on the water surface, as illustrated in Fig. 2(c). The mesh was transferred onto a\nslide glass for morphological analysis, confirmed through scanning electron microscopy (SEM)\nimaging, as shown in Fig. 2(d).\nChanges in manuscript: Result (Page 5, line 127)\nThe minimum thickness required for the mesh to stably float on water is 20 nm, allowing the ultrathin\nnanomesh to float on the water surface, as illustrated in Fig. 2(c). Films thinner than 20 nm,\nparticularly near 10 nm, exhibit severe embrittlement due to smaller grain size and reduced plastic\ndeformation capacity. This results in a high density of cracks and brittle fractures during deformation\n32, causing such thin films to hardly float on water. In contrast, 20 nm films retain sufficient ductility\nto withstand the floating and transfer process, establishing 20 nm as the practical lower limit for\nstable nanomesh flotation. Then, the mesh was transferred onto a slide glass for morphological\nanalysis, confirmed through scanning electron microscopy (SEM) imaging, as shown in Fig. 2(d).\nWe have added a concise explanation of these conditions in the revised manuscript. Thank you again\nfor this valuable suggestion.\nReference\n[1] Kim, Jae-Han, et al. \"Tensile testing of ultra-thin films on water surface.\" Nature\ncommunications 4.1 (2013): 2520.\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 3] One of the advantages of this WF-nTP technique is the conformability of the metal\nnanomesh. However, majority of the evidence are from SEM images. Is there any quantified data to\nprove this? Like signal to noise ratio? In other words, what are the benefits that the conformability will\nbring about?\nResponse: Thank you for your valuable comment regarding the need for quantitative evidence of\nconformability in our WF-nTP technique. While much of our initial evidence was based on SEM images,\nwe have now performed electrical impedance spectroscopy (EIS) measurements to provide further\nexperimental validation.\nEIS is widely used in plant monitoring to assess health and physiological status by measuring electrical\nproperties that are sensitive to changes in the plant tissue. To obtain accurate and reliable EIS data, it is\nessential that conductive electrodes form intimate and conformal contact with leaf surfaces. Poor\nelectrode contact introduces interfacial resistance and noise, degrading the quality of impedance\nmeasurements and obscuring meaningful physiological signals. Therefore, we compared the electrical\ncharacteristics of Au mesh electrodes conformally transferred onto plant leaves with those of\nconventional clip electrodes.\nAs shown in the attached experimental results, the Au mesh electrode, which was more conformally\nformed on the leaf surface, exhibited lower impedance and significantly clearer phase signals across a\nbroad frequency range (1 to 105Hz). This improved conformal contact between the mesh and the leaf\nsubstrate allows for minimized interfacial resistance and enhanced electrical coupling, resulting in\nlower impedance values at all measured frequencies. These are key benefits of the WF-nTP process.\nThese results support our claim that conformal transfer improves signal quality by reducing noise and\nenhancing electrode-substrate interfacing. Although a full set of quantification and systematic analysis\nis planned for future studies, we have included this representative data in the current manuscript to\ndemonstrate the practical functional advantage of mesh conformability. We appreciate your suggestion\nand have revised the manuscript to explicitly discuss this point.\nFig. S8 Comparison of impedance and phase characteristics of leaf with mesh and clip electrodes. a, Impedance\nspectra of the system measured using mesh (orange) and clip (green) electrodes across a wide frequency range\n(1 to 105Hz). The mesh electrode exhibits lower impedance compared to the clip electrode at all frequencies. b,\nCorresponding phase angle spectra as a function of frequency, showing clear signals for the mesh electrode,\nwhile the clip electrode displays slightly more noise.\nThank you once again for helping us strengthen the scientific rigor and clarity of our work.\nChanges in manuscript (Newly added part): Results (Page 8, line 192) Beyond morphological\nanalysis of conformal contact on the leaf, electrical impedance spectroscopy (EIS) was also\nconducted, as shown in Fig. S8. Since biological surfaces such as plant leaves exhibit both resistive\nand capacitive behavior, EIS is more suitable than simple surface resistance measurements. It\nprovides information on electrical properties of both the surface and internal structure including\nmoisture content and ion distribution, therefore EIS is widely used to monitor plant health 33. Given\nthat stable and clear impedance measurements require electrodes to conform closely to the surface,\nwe compared a conventional clip electrode with a single-layer Au mesh electrode transferred via WF-\nnTP. Both showed stable signals over a broad frequency range (1 to 105 Hz), but the Au mesh\nconsistently exhibited lower impedance at all frequencies, as shown in Fig. S8(a). In phase angle\nspectra, the clip electrode showed some noise, whereas the Au mesh produced very clear signals, as\nprovided in Fig. S8(b). These results demonstrate that the Au mesh produced by WF-nTP was\nconformally transferred onto the plant surface.\nChanges in manuscript (Newly added part): Methods (Page 17, line 463)\nElectrical impedance spectroscopy measurement\nElectrical impedance spectroscopy (EIS) was performed on plant leaves using both a conventional\nmetal clip electrode and a single-layer Au mesh electrode transferred via WF-nTP. The\nmeasurements, conducted over a frequency range of 1 Hz to 10⁵ Hz with 0.1V using a commercial\nimpedance analyzer (PalmSens4, PalmSens, Netherlands) compared impedance magnitude and\nphase angle under identical conditions.\nChanges in figure: The attached figure was added to the supplementary information. (Fig. S8)\nReviewer #3 (Remarks to the Author):\nThis study proposes a water-floatation-based nanotransfer printing technique (WF-nTP) for transferring\nnanostructures onto three-dimensional curved and hydrophobic surfaces, and demonstrates its potential\napplications in SERS and gas sensing. By modulating interfacial adhesion through plasma etching and\nutilizing water surface tension to achieve self-floating nanostructure transfer, the authors present a\nperspective that aims to overcome the limitations of traditional nTP techniques, which typically rely on\nadhesives or high-temperature processes. However, despite exploring a nanomanufacturing method, the\nstudy still shows significant shortcomings in technological innovation, experimental rigor, and practical\napplication potential, making it difficult to meet the breakthrough expectations of Nature\nCommunications. Below, I have listed some issues in this paper for the authors' reference, which will\nhelp facilitate subsequent revisions and submission to a more specialized journal.\nResponse: We appreciate your thoughtful and thorough evaluation of our manuscript. In response to\nyour comments regarding technological innovation, experimental rigor, and practical potential, we have\nmade a significant revision on the manuscript accordingly. The differences between our water-floating\nnanotransfer printing (WF-nTP) technique and conventional PVA-based transfer methods have been\nclearly emphasized, highlighting advantages such as process simplification, residue-free transfer, and\nbroad substrate applicability. Theoretical simulations of the nanomesh’s bending radius limit have been\nincluded to provide a mechanistic understanding of its conformability on curved surfaces. To validate\nSERS uniformity and enhance experimental rigor, additional Raman measurement and FDTD\nsimulations under realistic conditions were performed, further supporting our experimental\nobservations and optimizing multilayer structures. Additionally, the gas sensor performance has been\nthoroughly analyzed with expanded discussion on sensor response characteristics. These substantial\nimprovements reinforce the novelty, rigor, and applicability of our work. We appreciate your\nconstructive feedback, which has significantly enhanced the quality and clarity of the manuscript.\nWe believe these substantial improvements reinforce the novelty, rigor, and applicability of our work.\nWe would be very grateful if you could kindly reconsider our manuscript for publication.\nThank you again for your valuable time and constructive feedback.\n[Comment 1] The core transfer mechanism of WF-nTP relies on plasma etching to weaken the\ninterfacial adhesion, coupled with water surface tension to enable the floating and transfer of\nnanostructures. However, this principle has a significant overlap in physical mechanism with existing\ntransfer technologies based on sacrificial layers (such as the PVA fiber dissolution method) or interfacial\ntension regulation. Although WF-nTP omits the sacrificial layer preparation step, its primary innovation\nlies more in process optimization rather than principle innovation.\nResponse: We sincerely appreciate the reviewer’s insightful comment regarding the similarities in the\nunderlying physical principles of WF-nTP and existing transfer techniques employing sacrificial layers,\nincluding PVA dissolution or interfacial tension regulation. While both approaches utilize the concept\nof water surface tension to transfer structures, the WF-nTP technique is fundamentally a new process\nthat differs significantly from conventional methods. Given that it enables nanoscale pattern transfer\nunder simplified and residue-free conditions, WF-nTP offers expanded application possibilities and\nenhanced precision. To clarify these differences, we here compare the two main types of PVA-based\ntransfer methods with our WF-nTP technique and highlight its unique advantages.\n1. Metal Deposition on PVA Fiber Mats [ref 31 in our manuscript]\nIn this method, a metal layer is deposited onto a mat of PVA fibers by techniques such as sputtering or\nevaporation. The target substrate is then placed, and water is added to dissolve the PVA fibers, leaving\nthe metal film to be transferred onto the substrate. While this approach may appear superficially similar\nto WF-nTP, it is fundamentally limited in several key aspects.\nBecause the metal is deposited directly on randomly entangled or aligned PVA fibers, the transferred\nstructure is always a fibrous mesh. It is not possible to precisely control or design nanoscale patterns\nusing this method. In contrast, WF-nTP employs nanoimprint lithography to fabricate arbitrary\nnanoscale patterns, enabling highly regular and deterministic designs such as meshes, dot arrays, or\ncomplex device architectures. The inability to define or tune mesh geometry and periodicity in the PVA-\nfiber-based method severely restricts the range of achievable device functionalities, whereas WF-nTP\nremoves this limitation and supports on-demand fabrication of custom nanostructures.\nFor certain applications, such as electrodes, the PVA mesh transferring method may be sufficient due to\nthe inherently conductive, entangled metal network. However, for applications such as SERS,\ndensely patterned nanostructures with precisely controlled gaps are essential for achieving strong signal\nenhancement. PVA-fiber meshes generally form large, poorly controlled pores due to irregular fiber\nspacing, leading to suboptimal SERS performance. In this context, the patterning versatility of WF-nTP\noffers clear advantages, directly enabling superior device optimization for plasmonics, sensors, and\nelectronics.\n2. Thermal/Pressure-Assisted Transfer process\nA second approach seeks to address the limitations of the fibrous PVA method by patterning a metal\nnanostructured layer onto a flat film of PVA using heat and pressure. It is well known that thermoplastic\npolymers exhibit fluid-like behavior when heated above their glass transition temperature (T ). When\ng\nsufficient pressure is applied to the target material (metal) in contact with the substrate (polymer) at a\ntemperature above T , uniform contact is achieved between the two surfaces. In addition, the\ng\ntemperature change during and after transfer can induce mechanical interlocking between the structures.\n[1, 2] Given the thermoplasticity of PVA, nano-transfer printing onto PVA can be accomplished via this\nthermal/pressure-assisted process.\nThis strategy does allow the transfer of predefined metal nanostructures, thus overcoming the\nrandomness and lack of design control inherent to fibrous PVA mats. However, it requires significant\nthermal and/or mechanical pressure for pattern formation or delamination. Furthermore, PVA typically\ndissolves in water only at elevated temperatures (around 70 °C), making it difficult to completely\nremove PVA residue at room temperature. In contrast, our WF-nTP method does not require any thermal\nor mechanical pressure, which is a major advantage for delicate nanostructures and flexible devices.\nIn summary, although PVA-based transfer methods can transfer metal structures, they are limited either\nby the inability to define nanoscale patterns (PVA fiber mats) or by the need for high temperature and/or\npressure (thermal/pressure-assisted PVA films). WF-nTP overcomes these limitations by enabling\narbitrary, highly regular nanoscale patterning through nanoimprint lithography, free from the\nrandomness of fiber-based meshes. It operates at ambient conditions without thermal or mechanical\nstress, eliminating polymer residue issues and preserving delicate nanostructures and flexible substrates.\nThese advantages make WF-nTP a cleaner, more versatile, and higher-fidelity approach for functional\nnanofabrication compared with conventional PVA-based techniques. Moreover, WF-nTP represents a\nfundamentally new transfer process rather than an incremental improvement of existing methods,\noffering distinct patterning capabilities, broader application scope, and simplified process conditions,\nas emphasized throughout this study.\nReference\n[1] Zhao, Zhi-Jun, et al. \"Large-area nanogap-controlled 3D nanoarchitectures fabricated via layer-by-\nlayer nanoimprint.\" ACS nano 15.1 (2021): 503-514.\n[2] Ahn, Junseong, et al. \"Morphology-controllable wrinkled hierarchical structure and its application\nto superhydrophobic triboelectric nanogenerator.\" Nano Energy 85 (2021): 105978.\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 2] Why can the mesh conform to different curved surfaces? The authors did not provide\nquantitative data on the flexibility of the mesh itself (such as the bending radius limit), making it difficult\nto explain how it can adapt to high-curvature surfaces.\nResponse: We sincerely thank the reviewer for the thoughtful and constructive comment regarding the\nflexibility of the mesh and its ability to conform to various curved surfaces. This insightful feedback\nprompted us to deepen our analysis and provide a more rigorous quantitative explanation of the\nmechanical adaptability, which we believe strengthens the clarity and impact of our work.\nTo address the reviewer’s concern, we carried out a COMSOL simulation focusing on the mechanical\nbehavior of a single square mesh unit cell with the thinnest Au film thickness of 20 nm. The simulation\nwas designed by incorporating the mechanical properties of gold thin films and the specific geometry\nof the square open mesh pattern. We systematically analyzed the strain distribution within the unit cell\nwhen bent over radii ranging from 600 nm up to 5 μm.\nSince we simulated the result based on the maximum elastic region of the 20 nm thick Au film, we\nsought to determine the yield strain of this film thickness. From existing literature, it is known that a 20\nnm thick Au film typically experiences plastic deformation when subjected to strains exceeding\napproximately 2.2% [1]. This means that below this strain value, the 20 nm thick Au film behaves\nelastically. Using this critical strain value as a reference, we identified that the maximum strain within\nthe simulated unit cell reaches roughly 2.2% when the bending radius approaches approximately 800\nnm. This finding suggests that, under idealized theoretical conditions, the mesh composed of 20 nm\nthick Au exhibits a bending radius limit around 800 nm, beyond which plastic deformation is likely to\noccur.\nFFiigg.. SS66 SSiimmuullaattiioonn ooff bbeennddiinngg--iinndduucceedd mmaaxxiimmuumm ssttrraaiinn ffoorr AAuu mmeesshh uunniitt cceellll.. aa,, MMaaxxiimmuumm ssttrraaiinn vveerrssuuss bbeennddiinngg\nrraaddiiuuss,, ccaallccuullaatteedd bbyy CCOOMMSSOOLL ssiimmuullaattiioonn ffoorr tthhee mmeesshh uunniitt cceellll.. TThhee iinnsseett pprreesseennttss aann eennllaarrggeedd vviieeww ooff tthhee ffrroomm\n660000 nnmm ttoo 11 μμmm bbeennddiinngg rraaddiiuuss rreeggiioonn,, wwiitthh tthhee lliigghhtt bblluuee sshhaaddeedd aarreeaa hhiigghhlliigghhttiinngg tthhee rraaddiiuuss ((880000 nnmm)) wwhheerree\nmmaaxxiimmuumm ssttrraaiinn rreeaacchheess aapppprrooxxiimmaatteellyy 22..22%%.. bb,, VViissuuaalliizzaattiioonn ooff ssttrraaiinn ddiissttrriibbuuttiioonnss iinn tthhee mmeesshh uunniitt cceellll uunnddeerr\nbbeennddiinngg,, oobbttaaiinneedd ffrroomm CCOOMMSSOOLL ssiimmuullaattiioonn:: ttoopp,, tthhrreeee--ddiimmeennssiioonnaall ppeerrssppeeccttiivvee vviieeww aalloonngg tthhee ddiiaaggoonnaall;;\nbboottttoomm,, ccrroossss--sseeccttiioonnaall ssiiddee vviieeww sshhoowwiinngg ssttrraaiinn pprrooffiilleess aaccrroossss tthhee ssttrruuccttuurree..\nTo complement these theoretical insights, we also conducted experimental measurements of the actual\nc urvature radii present on the plant surfaces used in our study. We measured four points along the cross\nsection of the plant, as shown in Fig. 3(e). Using an image processing program, we were able to\ndetermine the curvature and radius of curvature at each measured point. This allowed us to characterize\nthe curvature distribution of the plant surface used. These measurements showed that the minimum\nradius of curvature is approximately 280 nm. Although the lower bound of this range can cause the\nstrain to surpass the elastic limit of a single unit cell, we observed that the mesh successfully conformed\nto the plant surfaces across this entire curvature range. This apparent discrepancy can be explained by\nthe fact that the mesh in real is composed of an array of unit cells rather than isolated structures. The\npresence of multiple interconnected cells allows for a redistribution of mechanical stress and grants the\nmesh greater overall flexibility and conformability. Thus, the mesh can accommodate higher local\ncurvatures than the theoretical bending radius predicted for a single isolated unit cell. In other words,\nthe array configuration introduces additional degrees of freedom that facilitate conformal adhesion to\ncomplex and highly curved surfaces. Furthermore, even when the plant surface curvature radius is\nbelow 300 nm, plastic deformation may occur locally in the ultrathin Au mesh during transfer. However,\nthis does not necessarily lead to fracture, as gold is a highly ductile metal capable of significant plastic\ndeformation before failure. Especially in ultrathin films, this ductility allows the Au mesh to bend and\nconform without fracture, enabling successful transfer even to surfaces with very small curvature radii.\nTherefore, local plastic deformation may be present, but the overall integrity and conformal contact of\nthe mesh with the substrate can still be maintained due to the intrinsic properties of gold and the arrayed\narchitecture of the mesh.\nFig. S7 Quantitative analysis of curvature and radius of curvature for 1-layer Au mesh transferred onto plant\nsurfaces. The curvature and radius of curvature at selected points were quantitatively analyzed using image\nprocessing of the plant cross sections. For each case, the lower graphs display the radius of curvature profile\nalong the section, highlighting the minimum radius of curvature measured (280 nm, 314 nm, 485 nm, and 421\nnm, respectively). These results demonstrate that the Au mesh can conformally adhere to plant surfaces with\ndiverse and high curvatures.\nIn summary, the combined simulation and experimental data clarify that the square open mesh with 20\nnm thick Au layer exhibits excellent mechanical flexibility and can conform to a wide range of curved\nsurfaces, including those with curvature radii on the order of hundreds of nanometers. We appreciate\nthe reviewer’s suggestion, as it provided an opportunity to present this quantitative mechanical analysis\nalongside experimental validation, thereby enhancing the rigor and completeness of our manuscript.\nWe have included this comprehensive explanation, supported by simulation data and detailed curvature\nmeasurements, in the revised manuscript to ensure that readers fully understand the mesh’s capability\nto adapt to high-curvature surfaces. We are grateful to the reviewer for prompting this valuable addition.\nOriginal manuscript: Result (Page 7, line 175)\nThe yellow line represents the Au mesh, which conformally follows the original contours of the\ncurved leaf surface. In the case of 3-layer mesh as depicted in Fig. S5(d), 3 layers of mesh also\nconformally formed along the original surface.\nChanges in manuscript: Result (Page 7, line 175)\nThe yellow line represents the Au mesh, which conformally follows the original contours of the\ncurved leaf surface. To quantify the bending radius corresponding to the elastic limit of the mesh\nstructure, we performed COMSOL simulations on a single unit cell of the mesh. From the simulation,\nthe bending radius corresponding to the elastic limit for the 20 nm thick Au mesh was estimated to\nbe approximately 800 nm, as shown in Fig. S6. However, it is important to note that this result reflects\nonly the local mechanical behavior of an individual unit cell and does not fully capture the\ncharacteristics of the entire mesh, which is composed of an array of such cells. To better understand\nthe practical bending behavior, we analyzed the cross-section of the plant surface shown in Fig. 3(e)\nthrough image processing to calculate curvature and radius of curvature (Fig. S7). This analysis\nrevealed that the smallest radius of curvature on the plant surface was about 280 nm. Interestingly,\nthe Au mesh was able to conformally bend over surfaces with radii of curvature smaller than the\nbending radius corresponding to the elastic limit estimated by the single unit cell simulation. This\nobservation indicates that the array architecture of the mesh imparts greater flexibility than what is\npredicted by the unit cell model alone, enabling the mesh to adapt to highly curved surfaces more\neffectively. Furthermore, even when the local radius of curvature of the plant surface is below 300\nnm, the Au can still be transferred without fracture due to its intrinsic ductility and ability to undergo\nlocal plastic deformation. As a result, the 20 nm-thick Au mesh maintains overall mechanical\nintegrity and conformability through plastic deformation rather than purely elastic deformation,\nenabling successful transfer even on surfaces with curvatures sharper than the theoretical elastic limit.\nIn the case of 3-layer mesh as depicted in Fig. S5(d), 3 layers of mesh also conformally formed along\nthe original surface.\nChanges in manuscript (Newly added part): Methods (Page 17, line 453)\nFinite element analysis\nFinite element simulations were conducted using COMSOL Multiphysics (Solid Mechanics module,\nCOMSOL AB, Sweden) to estimate the bending radius corresponding to the elastic limit of the\nsquare-open Au mesh. Au nanomeshes with thicknesses ranging from 100 nm down to 20 nm were\nconsidered; the thinnest case (20 nm) was analyzed in detail as it is expected to conform most stably\nto curved surfaces. A single square mesh segment (one opening with surrounding struts) was\nmodeled. Bending was imposed by prescribing a cylindrical curvature with radius R,\nsweeping R from 0.6 μm to 5 μm. For each R, the peak principal strain in the Au mesh was recorded.\nMaterials were modeled as isotropic linear elastic; plasticity was not included, as the objective was\nto identify the onset of yielding. Based on literature 53, a critical tensile strain of 2.2% was taken as\nthe yield threshold for the Au films, and the bending limit was defined as the smallest R at which the\ncomputed peak strain equals this value.\nChanges in figures: The simulation and quantitative analysis of curvature on leaf surfaces was added\nto supplementary information (Fig. S6 and S7)\nReference\n[1] Luo, Xue-Mei, and Guang-Ping Zhang. \"Deformation-mechanism dependent stretchability of\nnanocrystalline gold films on flexible substrates.\" Journal of Materials Research 32.18 (2017): 3516-\n3523.\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 3] The SEM image of the mesh on the fiber structure in Fig. 4d does not seem to be well\nbonded to the fiber structure, but rather lies flat on the fiber surface, lacking microscopic evidence of\ninterfacial bonding.\nResponse: Thank you for your comment regarding the interfacial bonding between the Au mesh and\nthe fiber structure shown in Fig. 4d. To provide direct microscopic evidence of conformal contact at the\ninterface, we performed focused ion beam (FIB) cross-sectional imaging of a 1-layer Au mesh\ntransferred onto a TPU fiber. As shown in Fig. S11, the cross-sectional SEM images reveal that the Au\nmesh closely follows the contour of the TPU fiber, indicating intimate, conformal contact without any\nobservable gaps or delamination. The higher-magnification image further confirms that the mesh is not\nmerely lying flat but is well adhered along the fiber surface at the microscopic level. These results\nsubstantiate that our transfer method achieves conformal integration of the Au mesh on the fiber,\ndirectly addressing the reviewer’s concern about interfacial bonding.\nFig. S11 Cross-sectional images of a 1-layer Au mesh on a TPU fiber. The left image shows a low-magnification\ncross-sectional image, indicating the conformal contact of the Au mesh on the TPU fiber. The right image\npresents a higher-magnification view of the same region.\nOriginal manuscript: Results (Page 10, line 247)\nFig. 4(d) shows the successful transfer of the Au mesh onto the fibers. Conventional nTP methods\nfor thermoplastic substrates such as TPU typically require thermal energy and high pressure,\npotentially damaging and deforming the substrate.\nChanges in manuscript: Results (Page 10, line 247)\nFig. 4(d) shows the successful transfer of the Au mesh onto the fibers. To further validate conformal\ntransfer, a cross-sectional image is shown in Fig. S11. Conventional nTP methods for thermoplastic\nsubstrates such as TPU typically require thermal energy and high pressure, potentially damaging and\ndeforming the substrate.\nChanges in Figure: The attached figure was added to supplementary information as Fig. S11\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 4] Single-point Raman testing cannot reflect the overall signal distribution. It is more\nconvincing to use mapping testing to statistically average the signal.\nResponse: We sincerely thank the reviewer for this constructive comment regarding the limitations of\nsingle-point Raman testing. We agree that signal mapping would provide more statistically robust\ninformation about signal distribution across the sample. Unfortunately, due to technical limitations of\nour Raman spectroscopy equipment, we were unable to perform full mapping measurements.\nTo address this concern, we measured the Raman spectra at six different points on the sample surface\nfor the 7-layer mesh, using Rhodamine 6G solutions at concentrations from 10-3 M to 10−6 M. As shown\nin the attached figure, the Raman peaks were consistently detected across all tested points for each\nconcentration, with signal distributions remaining comparable at every concentration level. These data\nindicate that, even in the absence of full mapping, the signal distribution across the sample is uniform\nand reproducible.\nAlthough we were unable to perform comprehensive mapping, we believe that the multi-point Raman\nmeasurements presented here adequately demonstrate the consistency and reliability of the signal\ndistribution in our samples. We appreciate the reviewer’s valuable suggestion and have incorporated\nthis explanation, along with the corresponding datasets and figures, into our revised manuscript to\nfurther clarify our methodology and strengthen the support for our results.\nFig. S15 Distribution of Raman signals measured at multiple positions on 7-layer Au mesh samples with\nRhodamine 6G. Raman spectra collected at six distinct locations on the 7-layer Au mesh using Rhodamine 6G\nsolutions at concentrations of 10−3 M, 10−4 M, 10−5 M, and 10−6 M. For each concentration, the representative\nspectra demonstrate consistent and reproducible signal profiles across different sample positions, supporting\nthe signal uniformity of the substrate.\nOriginal manuscript: Result (Page 12, line 306)\nR6G was detected at concentrations ranging from 10-3 M to 10-6 M using the seven-layer mesh. The\nRaman signal of 10-6 M R6G was also measured as a function of the number of layers, as shown in\nFig. 5(e).\nChanges in manuscript: Result (Page 12, line 306)\nR6G was detected at concentrations ranging from 10-3 M to 10-6 M using the seven-layer mesh. To\nevaluate the uniformity of the Raman signal across the substrate, measurements were taken at six\ndifferent points on the mesh surface for each concentration. As shown in Fig. S15, the Raman spectra\nobtained at these multiple locations exhibited consistent peak patterns and intensities, indicating a\nuniform signal distribution. The Raman signal of 10-6 M R6G was also measured as a function of the\nnumber of layers, as shown in Fig. 5(e).\nChanges in figure: The attached figure was added to the supplementary information as Fig. S15\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 5] The simulation results of the 3-layer mesh differ in the 1 layer (Fig. 5(f)), and the possible\nreasons need to be further explained. For the FDTD simulation of Fig 5c, the author only provides the\nelectromagnetic field simulation of the vertical nanogap, which is inaccurate for the entire multi-layer\nmesh system, and the effect of horizontal stacking randomness on the entire electromagnetic field\nshould be considered. In addition, after the Au mesh is bent, its vertical nanogap may not be 20 nm.\nResponse: We thank the reviewer for this constructive comment. We agree that our original FDTD\nanalysis in Fig. 5c focused on an idealized vertical nanogap and therefore could not capture the in-plane\nmisalignment that inevitably occurs in multi-layer meshes. In response, we extended the simulations to\ninclude horizontal stacking layers and examined how these layers modify the hot spots distribution and\noverall field enhancement as the number of layers increases. Given that the possible combinations of\nalignment cases are unlimited, it is impossible to simulate every configuration. Therefore, in response\nto the reviewer’s comment, we selected representative alignment cases for this simulation. Specifically,\nwe modeled four representative relative alignments within one unit cell period (PP): complete overlap\nwith (Δx, Δy) = (0,0) which is equivalent to (P, P), a half-cell shift along the x-axis (0.5P, 0), a quarter-\ncell diagonal shift (0.25P, 0.25P), and a half-cell diagonal shift (0.5P, 0.5P).\nFor each alignment scenario, we simulated stacks from 2 to 9 layers by assuming repeated layer patterns\nwhere the alignment of odd and even layers was repeated to simplify the simulation while still reflecting\nstacking randomness. For example, layers 2 and 4 share the same position, while the intermediate odd\nlayer carries the specified alignment offset. All other optical and material parameters used were identical\nto those of Fig. 5. We then extracted the maximum enhanced |E| field for each configuration.\nThe new results are presented in Supplementary Fig. S14, where (a) summarizes the maximum |E|\nenhancement for 2 to 9 layers across all four alignments and (b) visualizes the corresponding hotspot\nprofiles for the 7-layer case. As the reviewer anticipated, horizontal misalignment redistributes and\nsplits hot spots, causing their locations and intensities to vary depending on the layer number.\nImportantly, despite these variations, a robust trend emerges for every considered alignment, the\nmaximum |E| enhancement rises to an optimum near 6 to 7 layers and then slightly decreases. This\noptimum aligns well with our experimental observations and matches the inference made from our\noriginal vertical gap model, indicating that the principal conclusion (maximum enhancement near 7\nlayers) remains valid even when incorporating realistic horizontal misalignment effects in a vertical\nstacking. Given these results, the meaningful conclusion is not that the number ‘7’ itself is universally\noptimal, but rather that every multi-stacking structure has its own optimal number of layers depending\nFig S14. Effect of horizontal alignment on maximum E-field enhancement and hotspot distribution in\nmultilayer Au mesh structures. a, Maximum E-field enhancement (E/E ) as a function of the number of layers\n0\n(2 to 9 layers) for four different horizontal alignment cases: complete overlap (0, 0), half-cell shift along x\naxis (0.5P, 0), quarter-cell diagonal shift (0.25P, 0.25P), and half-cell diagonal shift (0.5P, 0.5P). Insets illustrate\nthe corresponding relative positions of individual layers for each alignment case and the red dashed square\nmarks the layer where the shift is applied. (b) Simulated hot spots distributions for each alignment configuration\nin the 7-layer mesh, showing the spatial distribution and locations of plasmonic hotspots for each stacking\nscenario.\non its geometric parameters and thickness. The exact optimum may vary depending on the structure,\nmaterials, and thickness of each structure, indicating that an optimal layer count should be identified\nfor each specific system rather than applying a single value across all designs.\nRegarding the difference observed between the 3-layer and 1-layer simulation results in Fig. 5f, our\nextended analysis and literature [ref. 10 in our manuscript] indicate that the introduction of multiple\nstacking and interfaces leads to inter-layer interference that can reduce the maximum |E| enhancement\nrelative to a single layer. Notably, previous studies have reported that a 2-layer stack may exhibit lower\nmaximum enhancement than a 1-layer stack since additional interfaces induce destructive interference.\nOur 3-layer calculation follows this behavior, showing a reduced maximum |E| compared to the 1-layer\ncase, whereas increasing the number of layers to 7 recovers and maximizes the enhancement prior to\nsaturation and slight decline.\nRef 10: Adv. Mater. 2016, 28, 8695 (Figure 3)\nFinally, we clarify that the original vertical gap simulation in Fig. 5c intentionally left the inter-layer\nspaces empty to isolate the role of the vertical nanogap under idealized conditions. Conversely, our\nexperimental Raman data were obtained from fully stacked meshes where both vertical coupling and\nin-plane misalignment coexist. Therefore, the experimental Raman result for the 3-layer case is\ninfluenced by both the vertical and horizontal gap effects, which explains the difference from the\nsimulated results shown in Fig. 5f. Although an exact, one-to-one replication of stochastic stacking\nconfigurations remains impractical, the additional alignment-inclusive simulations presented here\nprovide a deeper and more realistic interpretation of our experimental findings.\nWe appreciate the reviewer’s note that, after bending, the vertical nanogap of the Au mesh may not be\nexactly 20 nm. We agree that the actual inter layer spacing can vary locally due to bending induced\ndeformation and partial contact between layers. In our FDTD study we intentionally used a nominal 20\nnm gap as a theoretical baseline to describe the basic structure and to isolate the electromagnetic effect\nof stacking from mechanical irregularities. This idealized value provides a well-defined reference that\nallows the trends to be interpreted without additional free parameters.\nWe have incorporated these new results and detailed methods into the revised manuscript for results\nand added supplementary Fig. S14 for comprehensive documentation. We believe these revisions\nrobustly address the reviewer’s concerns and substantiate that the multi-layer mesh exhibits a\npronounced enhancement optimum around 6 to 7 layers, consistent with experimental evidence.\nOriginal manuscript: Result (Page 12, line 280)\nIn addition, the inconsistent e-field enhancement can be attributed to wave interference as it\npropagates through the multiple stacked layers. This interference can be either constructive or\ndestructive, leading to a nonuniform distribution of e-field enhancement across the mesh structure 10.\nAlthough directly correlating these results with the experimentally measured SERS intensity is\ncomplex owing to the integrated effect of various hotspots (horizontal and vertical gap arrays).\nChanges in manuscript: Result (Page 12, line 280)\nIn addition, the inconsistent e-field enhancement can be attributed to wave interference as it\npropagates through the multiple stacked layers. This interference can be either constructive or\ndestructive, leading to a nonuniform distribution of e-field enhancement across the mesh structure 10.\nConsistent with the literature on multi-stacked nanostructures for SERS 10, a two-layer stack can\nsometimes show a lower maximum enhancement than a single layer because additional interfaces\nintroduce destructive interference. Our three-layer calculation exhibits the same trend, resulting in a\nsmaller e-field enhancement than the single-layer case. To assess the robustness of this conclusion\nagainst horizontal layer alignment, additional FDTD calculations for four representative in-plane\nregistries between adjacent meshes across 2 to 9 layers were performed, with detailed results shown\nin Fig. S14. Given that the possible combinations of alignment cases are unlimited, we cannot\nsimulate every possible alignment configuration. Therefore, we performed simulations for several\nrepresentative and limited scenarios. We believe these simulations adequately capture the overall\ntrend observed in the multi-layer stacking effects on hot spot distribution and field enhancement. As\na result, while horizontal misalignment redistributes the hotspot locations, the maximum e-field\nenhancement still displays a clear optimum near 6 to 7 layers, consistent with the trends observed in\nFig. 5c and Fig. 5f. This suggests that the layer-dependent optimum is determined primarily by the\ninterplay between vertical coupling and field attenuation from multiple interfaces, rather than any\nspecific in-plane alignment. It should be noted that a direct one-to-one correspondence between\nsimulated enhancement and measured SERS intensity is not expected. The experimental\nmeasurement integrates signals from both horizontal and vertical hotspot arrays within a finite\nilluminated area. These factors, together with finite optical attenuation through the upper layers,\nexplain why the simulated three-layer case can yield a lower maximum e-field enhancement than the\nsingle layer while the experimental Raman intensity for three layers can differ from the trend of the\nidealized vertical gap model. Despite these complexities, the overall behavior aligns with the\nprevious study 10 and our supplementary alignment study in Fig. S14, supporting the conclusion that\nan optimal layer count of approximately seven exists for the present mesh geometry.\nAlthough Directly correlating these results with the experimentally measured SERS intensity is\ncomplex owing to the integrated effect of various hotspots (horizontal and vertical gap arrays).\nChanges in figure: The result of additional FDTD simulations on misalignment horizontal gaps were\nadded to the supplementary information as Fig. S14.\n---------------------------------------------------------------------------------------------------------------------------\n[Comment 6] The authors should provide the conversion process to the EU residue standard (μg/cm²)\nin the experimental details. Based on authors' mentioned information, it can be inferred that the author\ncalculated 6.49 µg/cm² based on an area of 1 cm². However, during the SERS measurement, the laser\nspot diameter corresponding to the 50x objective lens is usually at the micron level, which is much\nsmaller than the sample application area (1 cm²). Obviously, the result of 6.49 µg/cm² provided by the\nauthors is incorrect and should be higher than the EU standard. In addition, the detection limit of existing\nSERS technology for thiram is generally as low as nM level. The results in the manuscript (1 mM for\nleaf and 100 μM for fruit) are not competitive enough in terms of sensitivity. If the authors can prepare\na smaller grid structure, it may have more research value and practical significance.\nResponse: We thank the reviewer for raising these important points. In the revision, we now present\nthe explicit conversion to the EU residue metric in μg per cm² in the Methods section. The surface\nresidue density ρ is defined as the applied mass per wetted surface area and was calculated as:\nsurf\nρ [μg cm−2] = (C [mM] × V [μL] × 0.24043) / A [cm2]\nsurf sol applied wet\nHere, 0.24043 converts mM and μL to μg using the molar mass of thiram (M = 240.43 g mol⁻¹). C is\nsol\nthe thiram concentration in solution, V is the dispensed volume, and A is the wetted area\napplied wet\nmeasured. We now provide the explicit formula and a worked example in Methods. For our experiment,\na thiram solution of 1 mM with 27 μL drop cast on a 1.00 cm2 area yields a deposited mass of 6.49 μg,\ncorresponding to ρ = 6.49 μgcm−2 when the measured wetted area is 1.00 cm2. We emphasize that the\nsurf\nlaser spot size used for SERS acquisition is not the denominator of this metric, which is defined as\napplied mass divided by the actual wetted surface area.\nRegarding sensitivity, we appreciate the comparison to reports that quote nM-level detection limits for\nthiram. We note that such limits are typically obtained in extracted liquids or on smooth model\nsubstrates under controlled conditions that minimize matrix effects. Our measurements target direct on-\nleaf and on-fruit surfaces without extraction, where surface roughness, competitive adsorption, and\nbackground fluorescence reduce the attainable SERS gain. It is also important to note that the detection\nlimit required for thiram in our target applications is not as low as those reported in highly controlled\nenvironments. Even so, we agree that further improvement is valuable. A significant advantage of\nreducing the mesh pitch is the potential to increase the hotspot density within the interrogation area,\nwhich could further lower the practical detection limit. However, as our process relies on\nnanoimprinting (WF-nTP), realizing such structural changes requires fabricating new Si master molds\nwith modified patterns. Given the substantial cost and complexity involved in designing and\nmanufacturing initial master molds, we consider precise control of mesh pitch and related structures as\na future research direction. We appreciate the reviewer’s valuable suggestion regarding this point.\nChanges in manuscript (Newly added part): Method (Page 17, line 468)\nPesticide residue conversion\nThe surface residue density ρ is defined as the applied mass per wetted surface area and was\nsurf\ncalculated as:\nρ [μg cm−2] = (C [mM] × V [μL] × 0.24043) / A [cm2]\nsurf sol applied wet\nwhere 0.24043 converts mM and μL to μg using the molar mass of thiram (M = 240.43 g mol⁻¹).\nC is the thiram concentration in solution, V is the dispensed volume, and A is the wetted\nsol applied wet\narea measured.\n[Comment 7] There are some problems in H2 sensing applications: the sensor response is too low; the\ngas response time (1000s) is far behind the Pd-based sensors reported in the literature (response time\n<100s), which makes it difficult to support its application potential; the selectivity of the contrast gas is\nsmall (combustible gas) and the contrast gas concentration is too low; it should be compared with pure\nPd and literature materials.\nResponse: We thank the reviewer for their valuable and constructive comments. We respectfully clarify\nthat, while the absolute resistance change (ΔR) may appear modest, the signal-to-noise ratio (SNR) of\nour measurements is sufficient. The obtained responses are clear, stable, and highly repeatable at all\ntested H₂ concentrations. Sufficient SNR ensures reliable H₂ gas detection well above the noise floor,\nwhich is a key metric in sensing applications [1-3]. Importantly, our sensor demonstrates clear and\nselective H₂ detection even at concentrations below 1%, down to 0.25%. This low-concentration\ndetection capability is particularly valuable for practical safety monitoring where very small hydrogen\nleaks must be identified. While the absolute response at these concentrations may be lower, we highlight\nthat maintaining stable and reproducible detection at such low levels is a significant performance\nstrength of our device.\nWe appreciate the reviewer’s attention to the response time data and understand how the figure may\nhave led to some confusion. To clarify, the 1000 s noted on the time axis corresponds to the duration\nfor which hydrogen gas was administered in each cycle, rather than the sensor’s intrinsic response time.\nThe actual response time, defined as the period required to reach 90% of the total sensor signal change\n(t ) following H exposure, consistently ranges from 270 to 440 seconds across all measured\n90 2\nconcentrations (0.25 to 1%). We hope this clarification is helpful.\nWhile we acknowledge that our sensor exhibits a somewhat slower response time compared to some of\nthe fastest Pd-based devices reported in the literature, we would like to emphasize that, in practical\nsensing applications, parameters such as signal-to-noise ratio (SNR) and selectivity are often more\ncritical than response speed alone. Our sensor demonstrates strong SNR and excellent selectivity under\nrealistic conditions, which are decisive factors for reliable gas detection in real-world environments.\nNevertheless, we recognize that further improvement in response time would enhance the applicability\nof our sensor.\nTo address this, we decorated the Pd mesh with Pt nanoparticles to reduce the response time. Previous\nstudies have shown that incorporating Pt nanoparticles as a catalyst on Pd-based hydrogen sensors\nimproves response performance [4–6]. This is attributed to the spillover effect, wherein Pt facilitates\nrapid H dissociation and delivery to the Pd surface, accelerating PdH formation and ultimately\n2 x\nreducing the response time. In our experiments, Pt was deposited on Pd immediately after Pd deposition\nvia e-beam evaporation, creating approximately 5 nm Pt nanoparticles on the Pd mesh. The Pt-decorated\nPd mesh was then transferred onto electrospun TPU fiber via WF-nTP, and H sensing was performed\n2\nusing our established setup. As a result, the response time (t ) was reduced by about half across all\n90\ntested concentrations compared to the Pd-only mesh. For instance, at 1% H , the response time reduced\n2\nfrom 440 to 180 seconds. However, the overall response (R/R ) was lower than that of the Pd mesh,\nconsistent with previous reports, likely due to increased conduction from Pt [4, 5]. These findings\nsuggest that response time can be further improved by incorporating catalytic materials, though\noptimization of the Pt nanoparticle content and distribution is needed.\nThis optimization is currently ongoing and part of our future research plans; therefore, these preliminary\nresults have not been included in the manuscript. We thank the reviewer for raising this important point\nand hope these details help clarify our approach.\nIn terms of selectivity, we believe there may have been some misunderstanding regarding our sensor’s\nselective performance. Our contrast gases and their concentrations were carefully selected to reflect\nrealistic environmental scenarios for sensor deployment, following established occupational safety and\nenvironmental guidelines. Additionally, the parameters used in our selectivity tests both for gas type\nand concentration are comparable to those commonly adopted in the literature [1–2]. This approach\ndemonstrates that our sensor’s selectivity assessment is relevant and scientifically robust when\nbenchmarked against recent studies in the field.\nIn summary, our manuscript provides clear evidence of reliable SNR and reproducible detection\nperformance at low hydrogen concentrations (down to 0.25%), a moderate but practical response time\n(~400 seconds), and rigorous and application-relevant selectivity benchmarking. While sensor\nperformance figures such as SNR and selectivity are emphasized throughout our study, we would also\nlike to highlight that this work primarily demonstrates the potential and versatility of our fabrication\nprocess, paving the way for future sensor development and optimization. We believe these\nimprovements and clarifications fully address the reviewer’s concerns and thank you again for your\nthoughtful feedback and for giving us the opportunity to strengthen our work.\nReference\n[1] Ahn, Junseong, et al. \"Nanoscale three-dimensional fabrication based on mechanically guided\nassembly.\" Nature Communications 14.1 (2023): 833.\n[2] Ko, Jiwoo, et al. \"Nanotransfer printing on textile substrate with water-soluble polymer\nnanotemplate.\" ACS nano 14.2 (2020): 2191-2201.\n[3] Kim, Ki-Hoon, et al. \"Long-term reliable wireless H2 gas sensor via repeatable thermal refreshing\nof palladium nanowire.\" Nature Communications 15.1 (2024): 8761.\n[4] Kumar, Abhishek, et al. \"Platinum Decorated Palladium Nanowires for Room‐Temperature\nHydrogen Detection.\" Advanced Sensor Research 3.8 (2024): 2400013.\n[5] Li, Xiaowei, et al. \"Catalytically activated palladium@ platinum nanowires for accelerated\nhydrogen gas detection.\" ACS nano 9.3 (2015): 3215-3225.\n[6] Cho, Hee-Jin, et al. \"Pt-functionalized PdO nanowires for room temperature hydrogen gas\nsensors.\" ACS sensors 3.10 (2018): 2152-2158."}, {"round": 2, "reviewer_comments": {"reviewer_1": "The authors have addressed my comments reasonably well. I recommend acceptance and publication of the work.", "reviewer_4": "This study presents a water-floating-based nanotransfer printing (WF-NTP) technique, which enables the transfer of nanostructures onto various three-dimensional and hydrophobic surfaces without the use of toxic solvents or adhesives by floating the nanostructures and transferring them onto substrates through a \"scooping up\" process. This transfer method is simple to operate and highly efficient. Subsequently, the authors demonstrate the application potential of gold nanomeshes obtained via WF-NTP in surface-enhanced Raman spectroscopy and palladium nanomeshes in H₂ gas sensing.\nHowever, using water tension to separate nanostructures from the supporting substrate and then picking up the nanostructures with the target substrate is a very common strategy. Therefore, compared to previously published technologies, the innovation of this strategy is insufficient to support its publication in Nature Communications. Moreover, it is mainly applicable to grid-like nanostructures and has limitations for discontinuous nanostructures such as linear or dot-shaped ones. The authors' research group previously developed a method based on simple dissolution of a water-soluble nanopatterned polymer film for the facile transfer of nanostructures (ACS Nano 2020, 14, 2191–2201). I believe the scientific rigor and applicability of this published technology are stronger than those of the current manuscript.\nIn addition, I fully agree with the questions raised by the other three reviewers in terms of clarity, particularly concerning the clarity of responses to technical questions. There is also a formatting issue: there should be a space between numbers and units.", "reviewer_5": "The authors' responses in the revision have adequately addressed the reviewers' comments, and I consider the manuscript acceptable in its current form."}, "author_response": "RESPONSE LETTER\nDear reviewer:\nRe. Response to reviewer comments on “Versatile Water-floated Nanostructures for Three-\nDimensional Nanotransfer Printing” by Byung-Ho Kang, Ji-Hwan Ha, Yeongjae Kwon, Sohee Jeon,\nDonho Lee, Byeongmin Kang, Soon Hyoung Hwang, Junseong Ahn, Jun-Ho Jeong, and Inkyu Park.\nWe deeply appreciate the comments of the and have also incorporated significantly more\nreasoning, which has helped us improve the presentation.\nThe responses are colored in blue text.\nThe detailed response to the referee comments follows:\nREVIEWERS' COMMENTS\nReviewer #1 (Remarks to the Author):\nThe authors have addressed my comments reasonably well. I recommend acceptance and publication\nof the work.\nResponse: Thank you very much for your positive evaluation of our manuscript. We sincerely\nappreciate your time and constructive comments, which helped us improve the quality and clarity of\nthe work. We are grateful for your recommendation for acceptance and publication.\n---------------------------------------------------------------------------------------------------------------------------\nReviewer #4 (Remarks to the Author):\nThis study presents a water-floating-based nanotransfer printing (WF-NTP) technique, which enables\nthe transfer of nanostructures onto various three-dimensional and hydrophobic surfaces without the use\nof toxic solvents or adhesives by floating the nanostructures and transferring them onto substrates\nthrough a \"scooping up\" process. This transfer method is simple to operate and highly efficient.\nSubsequently, the authors demonstrate the application potential of gold nanomeshes obtained via WF-\nNTP in surface-enhanced Raman spectroscopy and palladium nanomeshes in H₂ gas sensing.\nHowever, using water tension to separate nanostructures from the supporting substrate and then picking\nup the nanostructures with the target substrate is a very common strategy. Therefore, compared to\npreviously published technologies, the innovation of this strategy is insufficient to support its\npublication in Nature Communications. Moreover, it is mainly applicable to grid-like nanostructures\nand has limitations for discontinuous nanostructures such as linear or dot-shaped ones. The authors'\nresearch group previously developed a method based on simple dissolution of a water-soluble\nnanopatterned polymer film for the facile transfer of nanostructures (ACS Nano 2020, 14, 2191–2201). I\nbelieve the scientific rigor and applicability of this published technology are stronger than those of the\ncurrent manuscript.\nIn addition, I fully agree with the questions raised by the other three reviewers in terms of clarity,\nparticularly concerning the clarity of responses to technical questions. There is also a formatting issue:\nthere should be a space between numbers and units.\nResponse: We appreciate the reviewer’s perspective and acknowledge that water-assisted floating and\ntransfer is an established concept. We also agree that the ACS Nano (2020) approach using a water-\nsoluble hyaluronic acid (HA) carrier enables transfer of isolated (non-grid) nanostructures, which are\nbeyond the scope of our current study. Our focus here is on optimizing the transfer of electrically\npercolating mesh-type networks and demonstrating how these networks can be directly multi-stacked\nfor SERS applications and used for H₂ sensing on real surfaces.\nWithin this defined scope, our method differs from the HA-carrier approach in two practical aspects, as\noutlined below.\nResidue management and multilayer stacking\nThe HA-based transfer relies on dissolving a polymer film. However, this process raises concerns about\nresidual organic contaminants, which can limit its applicability to systems that require residue-free and\nclean multilayer stacking. For SERS stacks, even trace polymer residues trapped between metallic\nlayers can act as dielectric impurities that reduce electromagnetic coupling and overall signal\nenhancement. In contrast, our water-floating approach does not employ a dissolvable carrier on the\ntarget side, eliminating the need for residue removal and thereby enabling clean, repeated stacking of\nmetallic meshes for multilayer SERS substrates.\nSurface compatibility\nWe achieve transfer to hydrophobic and topographically complex substrates by tuning the composition\nof the floating bath during the scoop-up step. In contrast, the HA-film method is implemented by placing\nthe polymer on a pre-wetted hydrophilic surface and dissolving it in situ, which intrinsically requires\ngood water wettability of the target. This creates a practical limitation for hydrophobic targets that our\nbath-tuned floating/transfer route is designed to overcome.\nIn summary, we acknowledge the reviewer’s point that the HA-based method can effectively handle\nisolated, non-grid nanostructures, which fall outside the intended scope of this work. This study aims\ninstead to provide a carrier-free, floating liquid-tuned transfer strategy optimized for percolating mesh-\ntype networks, enabling residue-free multilayer stacking and compatibility with hydrophobic surfaces.\nWe also appreciate the reviewer’s suggestion regarding formatting and will correct the spacing between\nnumbers and units throughout the revised manuscript.\n---------------------------------------------------------------------------------------------------------------------------\nReviewer #5 (Remarks to the Author):\nThe authors' responses in the revision have adequately addressed the reviewers' comments, and I\nconsider the manuscript acceptable in its current form.\nResponse: Thank you very much for your positive evaluation of our manuscript. We sincerely\nappreciate your time and constructive comments, which helped us improve the quality and clarity of\nthe work. We are grateful for your recommendation for acceptance and publication."}]

Decision letter