Subsurface mapping of nanofiller dispersion in polymeric coatings by quantitative electric force microscopy

摘要

Good dispersion of nanofillers in the polymer matrix is essential to optimize the performance of nanocomposite coatings. However, non-destructive characterization of nanofiller dispersion in coatings is a great challenge for traditional techniques. In this respect, electric force microscopy (EFM) is a promising tool to non-invasively map nanofillers dispersed in the polymer coatings. The main issue is how to quantify the measured EFM signal as a function of nanofiller depth, as the complex geometry of a commercial EFM probe makes the modeling of EFM signals difficult. Here we use custom-made ultra high aspect ratio EFM probe to map dispersion of carbon nanotubes and ZnO nanoparticles in various nanocomposite coatings. A model relating the measured EFM signal with the depth of nanofillers is proposed utilizing the simplified geometry of a custom-made EFM probe. This work demonstrates for the first time that quantitative EFM can be a valuable tool for subsurface imaging of nanofillers in polymer coatings with nanoscale spatial resolution.