Investigation of local piezoelectric properties of thin copolymer films

We used the scanning nearfield acoustic microscope−a nontouching profilometer−to investigate the local piezoelectric activity of thin vinylidene fluoride trifluoroethylene copolymer films with a lateral resolution of 1 μm. For metallized as well as uncovered polymers we measured the surface topography. By stimulating the previously poled films with an ac electric field, the piezoelectric surface motion could be measured with high local resolution. Additionally we investigated in detail the change of the piezoactivity during the poling process.