Ultra‐stretchable, anti‐freezing conductive hydrogels crosslinked by strong hydrogen bonding for flexible sensors

Abstract

Abstract Conductive hydrogel has shown unparalleled potential in flexible electronics. However, water‐based hydrogels will inevitably face deteriorated mechanical strength and ionic transport ability in low temperature, which may severely hinder their wide‐range application. To address the problem, we herein introduced a natural zwitterionic osmolyte (proline) and ammonium chloride (NH 4 Cl) as the anti‐freezing agent into a physically cross‐linked polyvinylpyrrolidone (PVP)/polyacrylamide (PAAm) hydrogel (PA gel), as inspired by the nature‐gifted anti‐freezing ability. The resulting conductive hydrogel demonstrated high stretchability (up to 3305%), and excellent ion‐conductivity (up to 11.8 S/m) and could withstand a low temperature (−40°C). Moreover, the gel‐based sensor showed sensitive dynamic response to different tensile rates and tensile strain. It is expected that the plant‐inspired anti‐freezing hydrogel will provide more possibilities for the application in flexible sensors.