Multiscale modeling of moisture diffusion in polymer/clay nanocomposites

In this paper, a multiscale approach is proposed to study the moisture diffusion behavior of polymer/clay nanocomposites. For this purpose, a new method to determine the representative elementary volume is proposed for possible nanocomposites structures. For this study, two structures at nanoscale are considered based on micrographs of the actual microstructures of these materials at this scale. The results, obtained for the in-depth profiles of the moisture content as well as the overall moisture diffusion kinetics curves revealed a significant effect of the clay volume fraction on the moisture diffusion in nanocomposites. Furthermore, the predicted results show, that the moisture diffusion behavior at microscale strongly depends on the structure at nanoscale. From these results, it seems that the exfoliated structure is the most critical for the moisture diffusion in polymer/clay nanocomposites.