Polymer/piezoelectric ceramic composites: Polystyrene and poly(methyl methacrylate) with PZT

Lead zirconate–titanate (PZT)/polymer composites have been prepared by in situ polymerization of styrene and methyl methacrylate around aligned, thin PZT rods. Hydrostatic piezoelectric coefficients (d̄_h and ḡg_h) measured by a dynamic technique yielded figures of merit (d̄_hḡ_h) roughly four times that of homogeneous PZT for as‐polymerized composites. When these composites were annealed at a temperature slightly below the glass transition temperature of the matrix polymer and repoled, d̄_hḡ_h increased nearly twofold due primarily to a reduction of the composite dielectric constant. The piezoelectric response was found to be essentially independent of frequency from 30 to 160 Hz.