Characterization of surface dead layer in VCF/TrFE nano films by means of broadband dielectric spectroscopy

The dielectric properties of thin films of copolymers of vinylidene fluoride with trifluoroethylene were examined. With assuming a layer at the surface that shows no ferroelectricity, the thickness dependence of the dielectric properties was analyzed. The temperature dispersion of the dielectric permittivity of the surface layer was estimated as well as its thickness. It was shown that the surface layer shows a small relaxation at the same temperature as that of the molecular motion in the bulk amorphous region, while the molecular motion is rather limited in the surface layer.