Double Response Composite Hydrogel With Large Reverse Bending Properties

ABSTRACT As a typical temperature‐responsive hydrogel, poly (N‐isopropylacrylamide) (PNIPAm) has been widely used to prepare responsive actuation layers of bilayer or multilayer composites to achieve behaviors such as bending or crawling. However, the weak interfacial bonding strength, insufficient responsive deformation, and single responsive type of the hydrogel limit its application in high‐performance multilayer hydrogel soft actuators. In this study, a temperature and light dual‐responsive bilayer hydrogel, PDMS‐MoS 2 /Ca/PNIPAm, was prepared by surface grafting polymerization. The material properties of both the hydrogel layer and the PDMS substrate were also discussed to achieve the desired bilayer responsiveness. In addition, the effects of pretreatment solution concentration, monomer concentration, and MoS 2 concentration on the performance of PDMS‐Ca/PNIPAm were also investigated. The results showed that optimizing the concentrations of benzophenone (BP) and NIPAm in PDMS‐Ca/PNIPAm bilayer hydrogels could improve their structural integrity and temperature responsiveness. In addition, increasing the MoS 2 concentration improved the temperature sensitivity and light responsiveness. At specific concentrations (BP 5 wt%, NIPAm 20 wt%, and MoS 2 7.5 mg·mL −1 ), the hydrogels exhibited the best dual‐response behavior with significant reversible bending. These findings provide better insight into the development of multilayer and multiresponsive hydrogel systems.