Tannic Acid-Enhanced Cellulose/PEDOT:PSS Films Exhibiting Low Electrical Hysteresis, UV Blocking, and Antibacterial Properties for Wearable Sensing

Wearable sensors for human motion monitoring demand soft, biocompatible materials with low mechanical and electrical hysteresis under repeated strain and environmental exposure. Here, we report a carboxymethyl cellulose (CMC)/tannic acid (TAC) hybrid film engineered for enhanced mechanical compliance, environmental resilience, and bifunctionality. Tannic acid acts as a natural cross-linker, conferring skin-like elasticity, UV shielding, and antibacterial properties. Integration of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) yields a conductive film with exceptional stretchability (up to 150%), low electrical hysteresis (∼4.86% at 100% strain), and high strain sensitivity (gauge factor ≈ 2.18 at 150%). The film enables accurate detection of diverse biomechanical signals, including joint movement, facial muscle activity, respiration, and laryngeal vibrations. UV absorption was significantly enhanced (1.58 A.U. at 350 nm; 4.39 A.U. at 330 nm), and bacterial growth was suppressed by 76%, addressing concerns of hygiene and device degradation in humid conditions. This multifunctional TAC@PEDOT:PSS hybrid presents a promising strategy for next-generation on-skin electronics, uniting mechanical robustness, electrical stability, and skin compatibility in a single platform.