Self‐Repairable Ionic Skin Based on Multiple Dynamic Bonds with Self‐Adhesive, Anti‐Freezing, and Antimicrobial Capabilities for Monitoring Human Motions

Abstract

AbstractBiomimetic ionic skins (i‐skins) have received intensive attention because of their capabilities to emulate various functions of human skin. However, challenges still remain in developing i‐skins with synergistic characteristics such as excellent mechanical properties, high strain sensitivity, freezing tolerance, and antimicrobial activity by a simple method. Herein, a hydrogel‐based i‐skin (P(AAc‐co‐CA)x) is facilely synthesized by one‐pot free radical copolymerization of vinyl choline‐asparagine ionic liquid (Cho‐Asn VIL) and acrylic acid (AAc) monomers using Al3+ as a crosslinker and bacterial cellulose (BC) as reinforcing agent, respectively. The resultant hydrogels integrate multiple excellent performances, including skin‐like modulus (100–300 KPa), superstretchability (2345 ± 97%), high self‐healing efficiency (93.7 ± 4.6%), recovery ratio (139.3 ± 7%) and conductivity (1.28 ± 0.06 S m−1), as well as transparency, self‐adhesiveness, antimicrobial activities, and biocompatible properties. Moreover, the i‐skins based on P(AAc‐co‐CA) x hydrogels exhibit high sensitivity (gauge factor (GF) of 2.77), rapid response time (300 ± 15 ms), and excellent durability to both tensile and compressive deformation, and thus can be used to monitor and distinguish human motions. Significantly, P(AAc‐co‐CA) x hydrogels can still maintain notable mechanical property, conductivity, and sensibility even at −20 °C. These integrated multiple advantages make P(AAc‐co‐CA) x hydrogels highly promising in the fields of i‐skins, flexible wearable sensors, and artificial intelligence.