Permeability modelling of polymer-layered silicate nanocomposites

With the addition of very low loading of exfoliated silicate fillers, the permeability of polymer-layered silicate nanocomposites remarkably decreases. In the paper, based on comparisons between experimental results and expectations of several existing models, we propose an improved tortuosity- based model, in which the random motion of gas/liquid molecules in a constrained environment is considered. We show that the pathway of a diffusing gas/liquid molecule in exfoliated polymer-layered silicate nanocomposites is akin to a self-avoiding random walk. The estimated critical volume fractions of clay fillers for the minimum permeability, in terms of the concept of renormalization, concur with available experimental data. (C) 2007 Elsevier Ltd. All rights reserved.