Piezoelectric and dielectric properties of siloxane elastomers filled with bariumtitanate

Abstract

Piezoelectric elastomers were prepared from suspensions of bariumtitanate (BaTiO3) particles in a telechelic polydimethylsiloxane (t-PDMS) by crosslinking the t-PDMS under an electric field. Crosslinking reaction was monitored by measurement of complex dielectric constant ε′ − iε″. Dielectric constant ε′ increased with increasing BaTiO3 content, and agreed approximately with the theoretical ε′ calculated with the Maxwell–Wagner theory. Piezoelectric constant d33 of the poled elastomers was measured by application of compressions in the direction of the poling field. It was found that d33 was of the order of 10−11 C/N and increased steeply with increasing content of BaTiO3 but became almost independent of composition in the range of BaTiO3 content from 3 to 14 vol %. To examine the effect of electric field on the aggregation structure of the particles, we observed light scattering of the suspension under an electric field, and found that the scattering pattern became anisotropic. This indicated that the particles are connected like a pearl necklace and are stretched in the direction of the poling field. The dependence of d33 on the volume fraction of BaTiO3 was explained by a model proposed by Banno. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 3065–3070, 1999