Abstract: Conductive hydrogels are ideal substrates for the preparation of flexible electronic devices due to their good electrical properties, tunable mechanical properties, ease of processing and biocompatibility. In this paper, maleic acid and acrylamide were used as comonomers, lithium chloride was used as the conductive ion, and N,N-dimethylbisacrylamide was used as the crosslinking agent to prepare conductive hydrogel by in-situ photopolymerization. The prepared hydrogel has a visible light transmittance of 93%, a maximum tensile deformation of~380%, and a maximum conductivity of 12 S/m. In view of its excellent comprehensive performance, a capacitive sensor was prepared using conductive hydrogel in the experiment and applied to human activity monitoring.The results showed that the prepared conductive hydrogel capacitive sensor exhibited sensitive response behaviors such as different degrees of finger bending deformation and finger touch of different strengths. Our method would play a role in promoting the development of wearable flexible electronics in future.

Key words: conductive hydrogel, conductive ions, capacitive sensor