Stretchable, conductive and anti-freezing poly (vinyl alcohol)-based organo-hydrogels for strain sensors

Conductive hydrogels have drawn significant attention in the field of stretchable sensors. However, the freezing and drying of water, the introduction of additional ions and ions leakage made the preparation process relatively complicated and significantly limited their long-term stability and safety. In this work, Poly (vinyl alcohol) – based organo-hydrogels were fabricated via photodimerization and freezing-thawing (F-T) cycles of the mixed solution of Polyvinyl alcohol bearing styrylpyridinium group (PVA-SBQ) and Poly (vinyl alcohol) (PVA). The as-prepared PVA-SBQ/PVA organo-hydrogels possessed good stretchability (389%), facture strength (0.39 MPa), conductivity (3.1 *10−4 S/cm at 25 ℃ and 4 *10−5 S/cm at −30 ℃) and temperature tolerance (−30 ℃). And the organo-hydrogels displayed a gauge factor of 1.6 at a strain of 100% and a low degree of hysteresis (5.34% at 100% strain). In addition, the as-prepared organo-hydrogels exhibited good low temperature sensing performance, which could monitor strain at − 30 ℃, making the organo-hydrogel suitable for use in the field of strain sensors. Therefore, it is believed that the PVA-SBQ/PVA organo-hydrogels offer a promising prospect for practical applications.