Fabrication of alginate‐P(SBMA‐co‐AAm) hydrogels with ultrastretchability, strain sensitivity, self‐adhesiveness, biocompatibility, and self‐cleaning function for strain sensors

Abstract Conductive hydrogels have attracted a myriad of interest due to their potential applications for human motion monitoring, personal healthcare diagnosis and so forth. However, fabrication of hydrogel‐based strain sensors integrating with ultrastretchability, adhesiveness, strain sensitivity, biocompatibility, and self‐cleaning function is still a challenge. Herein, a new type of semi‐interpenetrating multifunctional hydrogels, which integrated all above practical features magically were prepared via a facile one‐pot in‐situ radical copolymerization method. Thereinto, [2‐(methacryloyloxy) ethyl] dimethyl‐(3‐sulfopropyl) ammonium hydroxide (SBMA) and acrylamide (AAm) copolymers cross‐linked by N , N ′‐Methylenebisacrylamide (MBAA) served as the soft and functional matrix, whereas alginate was employed as the enhanced component. The transparent zwitterionic hydrogels had a max elongation and ionic conductivity of 1353% and 0.15 S/m, respectively. They could adhere onto various surfaces, including steel, glass, skin, and rubber. The repeatable adhesiveness, linear strain sensitivity within 0%–250% tensile strain and 0%–30% compressive strain provided remarkable working range and using stability. What's more notable was that the biocompatibility and self‐cleaning function tested by MTT, live/dead assay, allergy patch tests, and plate colony‐counting method imparted great possibility of practical application for strain sensors to hydrogels from a biological point of view.