Ferroelectric liquid crystalline elastomers (FLCEs) form a novel class of m
aterials, in which the properties of macroscopically oriented ferroelectric
liquid crystals can be combined with those of elastomers. The (direct and
the inverse) piezoelectric effect in these systems is measured and analyzed
on a molecular level. Backed also by x-ray measurements, a model is sugges
ted that interprets the observed piezoelectricity caused by electrically or
mechanically induced motions of smectic layers which are inclined with res
pect to the sample surface. The strength of the observed electromechanical
effects compares well with (or exceeds) that of classical piezoelectric mat
erials like barium titanate, lead zirconate titanate or poled polymers like
poly(vinylidene fluoride), making FLCEs an interesting candidate for appli
cations in microsystems technology. (C) 1999 American Institute of Physics.
[S0021-8979(99)06915-7].