Numerical Simulation of the Interaction Between Nanodielectrics and the Probe of Electrostatic Force Microscopy

摘要

Nanodielectrics has become main innovative insulating materials with excellent properties, mainly due to the interfacial region (atomic scale to tens of nanometers thick). It is shown that the microscopic interfacial environment will determine the macroscopic characteristics of materials. Therefore, developing direct detection methods of microscopic interfacial environment will play a key role in the future of nanodielectrics. Electrostatic force microscope (EFM) is a scanning probe microscope which uses the electrostatic interaction between the probe and the sample to characterize the dielectric properties of the interfacial region (up to nanoscale) on the sample surface. However, due to the geometrical size of the probe and the complexity of long-range electrostatic force and van der Waals force, the actual measured EFM signal will be difficult to decipher. Herein, the physical interaction process between EFM probe and typical nanodielectrics is studied by numerical simulation. The model consists of an inorganic spherical nanoparticle placed within the polymer matrix surrounded by interfacial regions. Permittivity and thickness of the interfacial region and particle-interphase depth were systematically investigated to figure out the sensitivity and signal intensity of the EFM probe. The results show that a lower permittivity of matrix, higher permittivity and thicker of the interfacial region, and lower nanoparticle-interface depth, all contribute to making the interfacial region easier to be detected.