A polyacrylamide/gelatin hydrogel with superior durability and weather resistance for sustainable wearable electronics

Abstract

Conductive hydrogels have recently been developed as potential materials for smart wearable devices. However, the low stabilities of conventional hydrogels significantly limit their lifespans in smart wearable electronics. Herein, we report a novel ion-conducting hydrogel that maintains excellent mechanical, electrical, and adhesive properties even after exposure to 25 °C and 76% relative humidity for 90 days or approximately 20 000 loading–unloading cycles. The introduction of LiCl and glycerol imparts PGLAG hydrogel with outstanding weather resistance. Furthermore, we found that during continuous loading–unloading cycles, the interactions of gelatin with polyacrylamide (PAM), and of acrylic acid bentonite (AABT) with the polymer matrix are progressively enhanced, gradually forming a robust “skeletal muscle” structure. This structure enables PGLAG hydrogel to undergo continuous loading-unloading cycles, resulting in a material that is not only intact but also exhibits progressively enhanced tensile strength (increasing from 154 to 220.22 kPa) and electrical conductivity (increasing from 0.30 to 0.45 S/m). Benefiting from its excellent weather resistance and durability, PGLAG hydrogel, as multifunctional sensors, exhibit real-time, fast, and stable signal response in detection of human motion, facial expression recognition and handwriting. These findings provide valuable insights into the design of enduring ion-conducting hydrogels for diverse applications.