The mechanical and electromechanical properties of calcium-modified lead titanate/poly(vinylidene fluoride-trifluoroethylene) 0-3 composites

Thin him composite sensors have been fabricated which incorporate piezoelectric ceramic particles in a polymer matrix. Such composites are more compliant than pure piezoelectric ceramics and can be embedded in thick structures to monitor internal mechanical conditions such as the evolution of damage. The mechanical properties and electromechanical interaction of composite films consisting of Ca-modified lead titanate particles in a poly(vinylidene fluoride-trifluoroethylene) matrix are examined in this paper. The viscoelastic properties of these composites (with various volume fractions, up to 60% ceramic) have been measured over a range of frequencies (0.01 to 100 rad s(-1)). These composite properties are primarily controlled by the viscoelastic properties of the polymer matrix, and are shown to depend greatly on frequency and ceramic content. The complex piezoelectric coefficients h(31)* and g(31)*, have been measured for these composites for various volume fractions and over a frequency range from 5 to 100 rad s(-1). The magnitudes and phase angles of the piezoelectric coefficients are also shown to be highly frequency dependent.