Thermoresponsive E‐Skin with Reversible Sweat Transport

Abstract Electronic skin (e‐skin) that adapts to dynamic environments requires simultaneous regulation of moisture and heat transport while maintaining reliable sensing capability. Here, a temperature‐responsive electrode based on a polypyrrole@poly(N‐isopropylacrylamide)@cellulose acetate)/poly[ N,N ‐dimethyl (methacryloylethyl) ammonium propane sulfonate]@cellulose membrane (PPy@PCA/PCM) bilayer is reported, which exhibits complementary wettability switching and reversible unidirectional water transport. At low temperatures, the electrode preserves moisture and heat, maintaining skin hydration level and temperature ≈4 and ≈5 °C higher than bare skin, respectively. At elevated temperatures, the wettability gradient reverses, promoting sweat evaporation and heat dissipation, with hydration level and temperature ≈6 and 4.2 °C lower than bare skin, respectively. Integrated into e‐skin, the electrode enables real‐time hydration and temperature sensing while dynamically regulating moisture and thermal flux when the environment changes, avoiding skin erythema after long‐term wear. Moreover, the PPy@PCA/PCM electrode shows excellent mechanical durability, chemical stability, and cytocompatibility. This adaptive electrode design offers a versatile strategy for multifunctional e‐skin that simultaneously ensures physiological signal fidelity and enhances user comfort under varying conditions.