An electrostatic force microscopy investigation of the dynamic properties of microscopic interface in nanocomposites

The microscopic structure and properties of the interfacial regions in nanocomposites considerably affect the dielectric properties such as dielectric constant, dielectric loss, and breakdown strength. In this paper, we developed a method based on electrostatic force microscopy (EFM) to characterize the structures and the dynamic dielectric responses of the interfaces in TiO₂/epoxy nanocomposites. The nanometer-scale resolution of EFM enabled direct detection of the temperature dependent dielectric response associated with the molecular dipoles of the epoxy chains at the interface between TiO₂ nanoparticles and epoxy matrix. In addition, different interfacial effects were obtained by the surface modification of TiO₂ nanoparticles. The EFM images showed that the investigated interfacial regions around the two types of TiO₂ nanoparticles exhibited different dielectric loss responses.