Synthesis and humidity sensitive property of cross-linked water-resistant polymer electrolytes

Defined structure and water-resistance are two important requirements for polymeric humidity sensors. Most of polymer electrolytes applied in humidity sensors do not bear both features at the same time. Herein, a novel method was used to develop stable humidity sensitive polymer electrolytes with defined structures. Nanoporous polymers based on 1,4-divinylbenzene (DVB) and methacrylatoethyl trimethyl ammonium chloride (DMC) were synthesized by free radical polymerization with a solvothermal route. The cross-linked structure could afford good stability of the polymers even at high humidity levels. The impedance module of the optimized sensor changed more than three orders of magnitude over the whole humidity range, with little humidity hysteresis and rapid response.