Trehalose-enhanced Anti-Freezing Conductive Hydrogels with High Stretchability and Low Hysteresis for Flexible Human-Machine Interaction

Abstract

Conductive hydrogels are regarded as highly promising flexible sensing matrix materials due to unique three-dimensional conductive network structure, high flexibility, tunable mechanical properties, and excellent ionic conductivity. However, the fabrication of flexible hydrogel sensors simultaneously achieving high stretchability, low hysteresis, anti-freezing properties, and conductivity remains a critical challenge. In this study, an ionic-conductive double-network hydrogel is prepared via thermal free radical copolymerization by integrating trehalose and lithium chloride (LiCl) into a polyacrylamide (PAM)/polyvinyl alcohol (PVA) double-network structure. Attributed to the dynamic hydrogen bonding network of trehalose that facilitates reversible energy dissipation, and the ionic conductivity of LiCl, the prepared hydrogel exhibited high stretchability (1202.0%), low mechanical hysteresis (< 3.0%), anti-freezing property (-27.5°C), and ionic conductivity (1.5 S/m). Furthermore, the assembled strain sensors and smart gloves enable sensitive detection of human motions, Morse code encoding transmission, and gesture recognition for robotic hands, highlighting the immense application potential of this hydrogel in human-machine interaction and wearable devices.