Multi‐Hydration Induced Zwitterionic Hydrogel with Open Environment Stability for Chemical Sensing

Hydrogels with open environment stability are of great significance in the fields of microelectronics, organ regeneration, and hydrogel‐based sensors. Although a series of strategies for exploring highly robust hydrogels have been proposed, it is still challenging to improve environmental stability while maintaining the original dispersed medium feature. Here, 1‐vinyl‐3‐butylimidazolium (VBIM) and acrylic acid (AA) are used as the anionic and cationic monomers to prepare zwitterionic hydrogels through the thermal initiation polymerization. The prepared PAA‐IL (polyacrylic acid‐co‐ionic liquid) hydrogel forms a large number of multi‐hydration, including hydrogen bonds and ion‐dipole interactions with water to inhibit the freezing and volatilization of water, and it possesses good structural stability due to the formation of ion bond self‐association through interchain charge interaction. The robust stability of the chemical sensor with PAA‐IL hydrogels as the substrate at different pH and temperature verifies the validity of the proposed design strategy. It is expected that the present zwitterionic hydrogel design strategy would shine a light on the exploration of environment‐stable hydrogels and hydrogel‐based chemical sensors. A zwitterionic hydrogel with open environment stability is prepared by copolymerization of two ionic monomers. Multi‐hydration improves the binding ability of ionic hydrogels to water, and the self‐association of ionic bonds between polymer chains improves its structural stability. The explored chemical sensors based on the polyacrylic acid‐co‐ionic liquid show good sensing performance and environmental stability to hazardous chemicals.