Double-network hydrogel-based stretchable, adhesive, and conductive e-skin sensor coupled human skin-like biocompatible and protective properties

Hydrogels-based wearable electronic skin (e-skin) sensors with multi-functions (e.g., good adhesion, high elasticity, fast and steady perceive ability toward the applied external stimuli, good compatibility, and human skin-like protective performance) are highly desirable in various disciplines including artificial intelligence, human health monitor, and soft robotics. However, they are several challenges that have to be addressed before going mainstream. Along these lines, in this work, a double-network hydrogel-based e-skin sensor is proposed to fulfil the above-mentioned challenges. The as-prepared hydrogels exhibit strong adhesion against diverse substrates and a high degree of elasticity (900.8 ± 46.4 % elongation at break). The fabricated strain sensor also displays high sensitivity (the gauge factor is as high as 2.57), fast response (245 ms)/recovery (247 ms) behaviour, linear response versus a broad strain range (0 % to 500 %), and robust stability (the response was not changed after the application of 2000 consecutive cycles). Most importantly, our hydrogel-based e-skin also holds good biocompatibility with human skin and strong antibacterial performance against harmful bacteria. Our findings pave the way for the development of next-generation human-skin-like sensors for practical applications.