Highly adhesive and conductive gelatin-based zwitterionic gels fabricated via efficient ultraviolet irradiation for...

Wearable gel sensors suitable for complex environments are highly desirable for next-generation flexible electronics. However, developing conductive biogels derived from gelatin with high adhesion, and stable sensing performance underwater or at low-temperature remains a great challenge. Herein, the multifunctional conductive zwitterionic gels based on gelatin were fabricated through ultraviolet-initiated copolymerization of sulfobetaine methacrylate and acrylic acid in the mixed solution of gelatin, tannic acid, and aluminum chloride. Unlike most reported gel sensors that mainly focus on improving the conductivity or mechanical strength, the zwitterionic gel simultaneously integrates robust adhesion, environmental adaptability, and reliable sensing capability through the design of dynamic crosslinking networks. The high stretchability (2000%), adhesion (100 KPa), self-healing efficiency (92%) and biocompatibility were attributed to the multiple non-covalent bonds including hydrogen bonds and electrostatic interactions in the gel matrix. By integrating the gel with a Bluetooth module, the wireless strain sensors based on this gel were capable of real-time monitoring the human join motion, facial expressions, smart writing, and underwater communication. In summary, this work not only proposes the design strategy for multifunctional gelatin-based gel sensors but also expands the applications of biogels toward portable and mobile monitoring within wireless wearable systems, with particular suitability for underwater and low-temperature environments that remain challenging for conventional gelatin-based gel sensors.