Enhanced piezoelectric properties of flexible PDMS sponges modified by PTFE solid films and nanoparticles

Polydimethylsiloxane (PDMS) sponges are widely used in many application areas due to their porous structure. In this paper, we present a PDMS sponge-based piezoelectric material which is composed of a PTFE-PDMS composite sponge sandwiched between a pair of Polytetrafluoroethylene (PTFE) solid films. After corona charging, pores inside the sandwich material are internally charged, and charges of positive or negative polarity are produced. The introduction of PTFE nano-particles creates PTFE-PDMS interface traps that can trap charges with stability. The design of the sandwich structure enhances the breakdown strength of the sandwich material, which avoids the early breakdown during poling. The results of the experiments demonstrate the sandwich material exhibits excellent piezoelectric performance and stability.