Transparent, Antifreezing, Ionic Conductive Cellulose Hydrogel with Stable Sensitivity at Subzero Temperature

Cellulose was dissolved in benzyltrimethyl ammonium hydroxide (BzMe₃NOH) aqueous solution, and ionic conductive cellulose hydrogels (CCHs) with antifreezing property were directly fabricated by chemical cross-linking, without further treatment. The concentrated BzMe₃NOH solution in the CCH matrix endowed the hydrogel with transparency, ionic conductivity, and freeze tolerance. CCH maintained transparency over 90% and stable mechanical properties in the temperatures from -27.8 to 62.1 °C. Furthermore, the CCH-based sensors exhibited stable sensitivity to tensile strain, compressive pressure, and temperature, in a wide temperature range including the subzero temperature, with a fast responding time and no obvious hysteresis. The present work is expected to provide a simple and sustainable pathway to prepare an antifreezing soft conductor with multifunctions based on cellulose, which enables a broad range of potential applications.