Characterization of Dielectric Nanocomposites with Electrostatic Force Microscopy

Nanocomposites physical properties unexplainable by general mixture laws are usually supposed to be related to interphases, highlypresent at the nanoscale. The intrinsic dielectric constant of the interphase and its volume need to be considered in the predictionof the effective permittivity of nanodielectrics, for example. The electrostatic force microscope (EFM) constitutes a promisingtechnique to probe interphases locally. This work reports theoretical finite-elements simulations and experimental measurementsto interpret EFM signals in front of nanocomposites with the aim of detecting and characterizing interphases. According tosimulations, we designed and synthesized appropriate samples to verify experimentally the ability of EFM to characterize ananoshell covering nanoparticles, for different shell thicknesses. This type of samples constitutes a simplified electrostatic model ofa nanodielectric. Experiments were conducted using either DC or AC-EFM polarization, with force gradient detection method. Acomparison between our numerical model and experimental results was performed in order to validate our predictions for generalEFM-interphase interactions