Ideal laminate theory for water transport analysis of metal-coated polymer films

We propose and validate a diffusion model, based on the ideal laminate theory (ILT), to describe water transport through metal-coated polymer films for barrier applications. The physical properties required for numerical implementation are studied. The analysis reveals that the solubility of the metallic coating is not required for an accurate water transport analysis, which makes the ILT-based model practical. The model is implemented numerically and the results are compared with the experimentally measured transient water weight gain of PET films with Al and Cr coatings to corroborate the validity of the model.