## 3 Results  
### Fabrication of the ENMH  
To ensure consistent fiber morphology, the electrospinning parameters were systematically optimized prior to device fabrication [29]. Specifically, PVDF-HFP solutions with concentrations of 18, 20, 22, and 24 wt% were evaluated (Figure S1a). At lower concentrations (18-20 wt%), insufficient chain entanglement due to low solution viscosity led to Rayleigh instability and frequent bead formation on the fiber surface [30; 31]. At 24 wt%, the solution exhibited excessive viscosity, resulting in nozzle clogging and poor jet elongation, ultimately yielding thick and nonuniform fibers [32]. In contrast, the 22 wt% solution provided an optimal balance of viscosity and entanglement, enabling the formation of uniform, bead-free nanofibers with stable morphology.  
Further optimization was conducted by varying the applied voltage from 10 to 16 kV using the 22 wt% solution (Figure S1b). Stable jets and straight fibers were obtained at 10-12 kV, while voltages above 14 kV caused excessive whipping and coiling due to high charge density [33]. Such coiled morphologies led to increased fiber overlap and reduced conductivity, making them unsuitable for heating applications. At voltages exceeding\(16\) kV, the imbalance between electrostatic forces and surface tension induced the formation of irregular blobs and significantly increased fiber diameter variability. Based on these findings, an applied voltage of 10-12 kV and a polymer concentration of 22 wt% were selected as the optimal electrospinninging conditions for producing uniform nanofibers with high structural integrity.  
The fabrication process of the ENMH is schematically illustrated in Figure 1. A nanofiber membrane was first prepared via electrospinningning of a PVDF-HFP solution under a high-voltage electric field, producing a flexible, nonwoven web composed of uniform, interconnected fibers. The electrospun PVDF-HFP nanofibers exhibited an average diameter of 349.1 \(\pm\) 101.1 nm, with most fibers falling within the 250-500 nm range and a peak frequency observed in the 300-400 nm interval. This result is consistent with the commonly reported diameter range for PVDF-HFP-based nanofibers in the literature (approximately 300-700 nm) [34; 35]. For example, [PERSON] et al. reported an average fiber diameter of approximately 500 nm when electrospinningning a 17 wt% PVDF-HFP solution under conditions of 15 kV and 0.3 mL/h [36], which is comparable to the fiber dimensions obtained in this study. Such fiber diameters are considered optimal for maintaining structural integrity while providing a high surface area during subsequent metallization processes. The ENM exhibited a hydrophobic surface with a static contact angle of 128.0\({}^{\circ}\), indicating poor wettability (Figure 1a). To improve wettability and enable subsequent solution-based modifications, the ENM was treated with a 5 wt% SDBS solution, which rendered the surface hydrophilic and reduced the contact angle to 30.8\({}^{\circ}\) (Figure 1b). Following this treatment, the adsorption of the anionic surfactant SDBS onto the PVDF-HFP fiber surface induced a swelling effect, resulting in an increase in the average fiber diameter to 498.5 \(\pm\) 150.9 nm--a 42.8% increase compared to the untreated fibers (Figure S2).  
Following this, the SDBS-treated ENM was immersed in a BSA solution, resulting in the formation of a protein-based interfacial layer (Figure 1c). The BSA/SDBS-ENM was then treated with a Pd solution, allowing Pd\({}^{2+}\) ions to bind electrostatically to the functional groups of the BSA layer (Figure 1d). Electroless Cu plating was subsequently performed on the Pd/BSA/SDBS-ENM (Figure 1e). In the presence of formaldehyde as a reducing agent, Cu\({}^{2+}\) ions were spontaneously reduced at the Pd catalytic sites, forming a conformal and continuous Cu layer across the nanofiber web. Finally, conductive silver paste was applied to both ends of the Cu/Pd/BSA/SDBS-ENM to attach wires, completing the ENMH device configuration.