Hydroxyethylcellulose and In Situ Formed Crosslinked Poly(Acrylamide-Co-2-Acrylamido-2-Methylpropanesulfonic Acid) Based Calcium Ion Embedded Conductive Composite Hydrogels for Flexible Electronic Devices

Abstract

Ionic conductive hydrogels (ICHs) have received much attention as ideal candidates for flexible electronic devices. However, conventional ICHs have not been widely used due to their inability to simultaneously possess high toughness and high ionic conductivity. Here, an interpenetrating double network hydrogel designated as HPPC was prepared by photocopolymerizing AM, AMPS, and MBA in the presence of HEC and CaCl₂ using irgacure as a photoinitiator. Hydrogen bonding between the HEC and P(AM-AMPS) formed the interpenetrating network structure. Calcium ions functioned as ionic cross-linking agents and conductive ions, effectively dissipating energy. A tensile strength of 0.101 MPa, 648% tensile strain, and satisfactory ionic conductivity were exhibited. In addition, the flexible strain sensor based on HEC/P(AM-AMPS)/CaCl₂ hydrogel has excellent sensitivity and can accurately record the movement status of different body parts of the human body. Notably, the specific capacitance of HEC/P(AM-AMPS)/CaCl₂-CS can reach 30.5 F g⁻¹ at a current density of 1 A g⁻¹. Overall, this ion-conductive hydrogel has potential for flexible electronics.