Frost-Resistant and Self-Healing Enhanced Hydrogel for Wearable Sensors and Electronic Skin

Abstract

Recent progress in hydrogel engineering has concentrated on the creation of multifunctional materials tailored for the advancement of next-generation wearable electronic devices. This study presents an anti-freezing, self-healing hydrogel engineered by integrating lithium bis(trifluoromethane)sulfonimide (LiTFSI) into a copolymer network of acrylamide (AM) and N-[tris(hydroxymethyl)methyl] acrylamide (THMA). The triple hydrogen-bond network endows the hydrogel with a fracture strain of 1,023%, tensile strength of 103.8 kPa and toughness of 501.6 kJ⸳m-3. LiTFSI suppresses water crystallization while enhancing ionic conductivity. As a strain-sensing element, the material achieves a Gauge Factor (GF) of 9.09 with 107 ms response and 104 ms recovery time. It maintains reliable performance throughout 300 cyclic tests, enabling precise tracking of physiological motions and other complex movements. Its inherent adhesive properties and autonomous self-healing capabilities highlighted its potential applications in prosthetics, human-machine interfaces, and wearables designed for extreme environments. This minimalist ternary hydrogel integrates anti-freezing, self-healing, and sensing capabilities while enhancing electrical performance, thereby significantly improving applicability in complex environments.