Synthesis of dual cross-linked ion conductive temperature-sensitive hydrogel and its application in tunable smart window

Intelligent hydrogels are widely studied for their unique responsiveness, but single responsiveness limited the application of hydrogels. Compared with traditional electronic conducting hydrogels, ionic conducting hydrogels have good transparency, mechanical properties, and wear resistance, but the preparation of conductive hydrogels with stability, and multi-functional response is still a difficult challenge. This work reports a preparation strategy for the development of dual cross-linked poly(N-isopropylacrylamide-co-acrylic acid) P(NIPAM-co-AA) hydrogel through rapid photopolymerization. N,N′-methylenebis-acrylamide (BIS) is used as a cross-linking agent to form chemical cross-linking. At the same time, by introducing AA and Al 3+ to form electrostatic and coordination interactions, the hydrogel has enhanced conductivity and exhibits adjustable low critical solution temperature behavior. The hydrogel achieved visual temperature response, enhanced mechanical properties, and stable electrical conductivity. The hydrogel can be applied to visual qualitative detection of the intelligent windows by using the high sensitivity temperature response characteristics. Stable high conductivity also motivates the design of thermo-sensitive sensor windows and visual detection materials. This study will promote the synthesis of hydrogels with multiple response capabilities and realize their applications in smart devices.