New Insights into Dielectric Nanocomposites by EFM Imaging and Spectroscopy

There is currently no reliable method for studying interfacial regions within dielectric nanocomposites. The aim of this work was to develop experimental protocols and signal analysis involving Electrostatic Force Microscopy (EFM). Model samples made of spherical nanoparticles deposited on a metallic substrate and covered by two shells were designed and fabricated to simulate the presence of an interphase between a particle and a matrix. EFM performed either with DC or AC gradients detection method proved good sensitivity to certain sample configurations. A quantification of the dielectric permittivity of the intermediate layer was possible thanks to correlation with finite element numerical simulations. Interfacial states between stacked layers, which can be attributed to film deposition processes, were also evidenced.