Understanding piezoelectric characteristics of PHEMA-based hydrogel nanocomposites as soft self-powered electronics

Piezoelectric hydrogel nanocomposites are being developed as interface for connecting biological organs and electronics because of their flexibility, biocompatibility, and electromechanical behaviours, which allow environmental stimulations to be converted into electronic signals. The vision of this work is to develop a series of piezoelectric hydrogel nanocomposites which is capable of generating electric current in aqueous condition. Conductive nanoparticles have been composited in the PHEMA-based hydrogel. Theoretical models and characterisations on the electromechanical properties of such hydrogel have been investigated to assist the understanding of the piezoelectric mechanisms. The hydrogel nanocomposite was demonstrated as a self-powered motion sensor to quantitatively detect human motion and can be considered as candidate material for soft energy harvesting electronics. Overall, the work presented in this paper provides theoretical basis, design guidelines, and technical support for the development of soft self-powered electronics, thus unlocking the potential of piezoelectric hydrogel nanocomposites.