Computation-guided design of flexible piezoelectric composites by optimizing charge-stress transmission

Abstract

Flexible piezoelectric materials have attracted increasing attention as active components in wearable and flexible electronics, soft robotics and artificial skins or muscles. Although constructing polymer-based composites is becoming a common solution to balance their piezoelectricity and flexibility, challenges associated with the electrical and mechanical mismatch between the polymer matrix and the ceramic fillers remain. Here, taking the piezoelectric composite of lead zirconate titanate-polydimethylsiloxane (PZT/PDMS) as the example, we perform phase-field simulations to spatially and temporally study the electrical and mechanical response. It is found that good connectivity of fillers could provide a load transfer path and break topological restriction of filler morphology on polarization dipoles. Then, we propose an interface design strategy to address the mismatch problem in ‘3–3’ composites, which could greatly enhance the overall piezoelectric response under different modes of compressing, stretching and bending. Finally, we experimentally fabricate high-performance flexible composites with an ultrahigh piezoelectric charge coefficient of 155 pC N−1 and a low Young’s modulus of 63 MPa. This research offers a promising route for designing flexible piezoelectric composites by synergistically regulating connectivity and mismatch problems, which is also expected to guide the optimization of other actuators or sensors related with electromechanical coupling effect.