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.