Abstract

A mathematical model was developed to describe mass transport in polymeric films based on modifications of Fick’s law in a continuous macroscopic approach. The purpose of this work was specifically to model the transport of water vapor and oxygen in polymeric films at the pore level, based on physical aspects of the condensation process and the morphology and connectivity of the porous medium, with two-dimensional pore networks representing pore spaces. Using a Pore scale discrete model, we found that the pore-level distributions of liquid (condensate) and vapor as transport phenomena occurred. The vapor and oxygen diffusivities ranged from 4.22×10-6 to 3.16×10-7 cm2/s and from 3.66×10-6 to 2.86×10-7 cm2/s, respectively. Also, the vapor and oxygen permeabilities ranged from 2.61×10-3 to 3.83×10-4 nD (1nD=10-21m2) and from 6.77×10-3 to 1.35×10-3 nD, respectively. The transport properties obtained by the model were compared with the corresponding results for chitosan films obtained in previous experimental studies, showing a partial agreement