## 5 Conclusions  
In conclusion, the ENMH system developed in this study exhibits a distinctive combination of performance attributes that address key limitations in current flexible heating technologies. Compared to previously reported platforms, the ENMH enables uniform heat distribution through a conformal and continuous Cu coating, mechanical compliance without the need for structural patterning, and stable operation within the skin-safe temperature range (40-50 \({}^{\circ}\)C) under an ultra-low input voltage of 0.4 V. In addition, the device demonstrates excellent electrical and thermal stability under repeated mechanical deformation, without relying on auxiliary functional layers. These advantages are achieved through a solution-processed, pattern-free fabrication route that is inherently scalable and compatible with curved or wearable substrates. Collectively, these results highlight the ENMH's strong potential as a high-performance thermal platform for practical deployment in next-generation wearable electronics and smart textile applications [1, 62]. The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/app15148023/s1](https://www.mdpi.com/article/10.3390/app15148023/s1)]([https://www.mdpi.com/article/10.3390/app15148023/s1](https://www.mdpi.com/article/10.3390/app15148023/s1)), Figure S1. Morphological analysis of electrospun fibers under varying conditions. (a) SEM images of electrospun fibers with different polymer concentrations in the spinning solution (18, 20, 22, and 24 wt%). (b) SEM images of electrospun fibers fabricated under different applied voltages during electrospinningning (10, 12, 14, and 16 kV). Figure S2. Diameter distribution of electrospun nanofibers. (a) Frequency histogram of nanofiber diameters immediately after electrospinningning. (b) Frequency histogram of nanofiber diameters after immersion in SDBS solution. Figure S3. Photographic images of ENMH and ENMH(\(-\)BSA step), with surface conditions before and after the peel test. From left to right: Cu-coated nanofiber membrane before the peel test, after the peel test, and adhesive surface of the peeled tape. (b) 3D AFM images of the tape surface after a single peel test for both ENMH and ENMH(\(-\)BSA) samples (scan area: 20 \(\times\) 20 \(\mu\)m\({}^{2}\)). Figure S4. Variation in sheet resistance of ENMH(\(-\)BSA step) over repeated peel test cycles. Figure S5. Thermal performance evaluation of the ENMH(\(-\)BSA step). (a) Stepwise voltage increase in 0.1 V increments every 30 s. (b) Short-term cyclic heating behavior under repeated ON/OFF switching of 0.6 V at 10 s intervals. Figure S6. Environmental durability evaluation of the ENMH. (a) Temperature response of the ENMH under oxidative conditions (85 \({}^{\circ}\)C for 48 h) during stepwise voltage increments of 0.1 V every 30 s. (b) Temperature response to the same voltage increments after exposure to a humid environment (85% relative humidity at 25 \({}^{\circ}\)C). Figure S7. Evaluation of wash durability. (a) Surface SEM and EDS images of the ENMH after washing under different conditions. (b) Comparison of electrical conductivity corresponding to each washing condition. Table S1. Comparison of the heating performance with recently reported textile-based wearable heaters. References [40-46] are cited in the supplementary materials. Conceptualization, G.H.K. ; methodology, M.J.C. and D.H.Y. ; validation, M.J.C. and D.H.Y. ; formal analysis, M.J.C., D.H.Y. and H.N. ; investigation, M.J.C. and D.H.Y. ; resources, G.H.K. ; writing--original draft preparation, H.N. ; writing--review and editing, H.N., Y.S.P. and G.H.K. ; visualization, M.J.C., D.H.Y. and H.N. ; supervision, G.H.K. ; project administration, G.H.K. ; funding acquisition, H.N. and G.H.K. All authors have read and agreed to the published version of the manuscript.