Nanoscale surface charge detection in epoxy resin materials using electrostatic force spectroscopy

Electrostatic force spectroscopy (EFS) operated in a conventional force gradient detection method allows determining local surface charges in epoxy samples. This is made possible through a detailed analysis of gradient versus DC voltage curves. The parabolic dependence of these curves is closely related to the charge density. Both maximum and origin-ordinate are key data from which it is possible to extract quantitative information on the detected charge. The study is based on the combined use of numerical and analytical simulations of the probe sample interaction. Excellent sensitivities to very low surface charge densities are reported.