Local dielectric spectroscopy of nanocomposite materials interfaces

Local dielectric spectroscopy is performed to study how relaxation dynamics of a polyvinyl-acetate ultrathin film is influenced by inorganic nanoinclusions of a layered silicate (montmorillonite). Dielectric-loss spectra are measured by electrostatic-force microscopy in the frequency-modulation mode in ambient air. Spectral changes in both shape and relaxation time are evidenced across the boundary between pure polymer and montmorillonite sheets. Dielectric-loss imaging is also performed, evidencing spatial variations of dielectric properties near nanostructures with nanometer-scale resolution.