Construction of Carboxymethyl Chitosan Hydrogel with Multiple Cross-linking Networks for Electronic Devices at Low Temperature
Yang Wang, Wenbo Zhang, Xinhu Gong, Caimei Zhao, Yiying Liu, Chaoqun Zhang
Abstract
On the basis of the original hydrogen bonding interaction and physical entanglement, covalent cross-linking and ionic cross-linking were additionally introduced to construct a carboxymethyl chitosan/allyl glycidyl ether conductive hydrogel (CCH) through a one pot method by a graft reaction, an addition reaction, and simple immersion, successively. The multiple cross-linking networks significantly increased the strength of CCHs and endowed them with ionic conductivity and an antifreezing property at -40 °C, which showed stable, durable, and reversible sensitivity to finger bending activity at subzero temperature. The CCHs could even be assembled into a triboelectric nanogenerator (TENG) to provide electric energy, which demonstrated stability against temperature variation, multiple drawing, long-term storage, or large quantities of contact-separation motion cycles. CCH-TENG can also be used as a tactile sensor within the pressure range from 0.4 kPa to higher than 8000 kPa. This work provided a simple route to fabricate antifreezing conductive hydrogels based on carboxymethyl chitosan and to find potential applications in soft sensor devices under a low temperature environment.