Improved polyacrylamide/chitosan dual-network hydrogels through the synergistic effect of aluminum ions and imidazolium ionic liquids toward flexible capacitors and sensors

Conductive hydrogels have been widely used in the fabrication of flexible capacitors and wearable sensors. However, traditional hydrogels often struggle to strike a balance between electrochemical performance and mechanical properties, and issues such as poor durability and stability remain unresolved. Herein, based on the polyacrylamide/chitosan (PAM/CS) dual-network hydrogel, we introduced the AlCl 3 and 1-decyl-3-methylimidazolium perchlorate ([DMIM][ClO 4 ]) ionic liquid (IL) with the guidance of molecular dynamics simulations. The introduction of ionic liquids (ILs) not only promotes ionic transport but also enhances various interactions (hydrogen-bonds and coordination-bonds), reconfigures the solvation structure of Al 3+ , and significantly improves the mechanical properties and conductivity of the hydrogel. In particular, the maximum tensile strain of the PCA-3IL hydrogel increased to four times that of PCA, reaching 856%, and the ionic conductivity doubled to 33.1 mS cm -1 . In addition, the specific capacitance of the capacitor constructed using the target hydrogel was approximately 87.9% higher than that of the hydrogel capacitor without IL added. The assembled flexible wearable sensor also exhibited excellent sensitivity and fatigue resistance, and is capable of accurately detecting even the slightest handwriting movements. Therefore, this design method can be considered an effective strategy for enhancing the overall performance of traditional hydrogels. The hydrogels prepared by this method have great potential for applications in flexible capacitors and sensors.