Solvent Diffusion Modeling in Silicone

The diffusion of solvents into a polymer matrix is critical in various applications such as medicine and electronic coatings. Previously, one-dimensional modeling of solvent diffusion in a highly cross-linked epoxy resin was successfully established using the PC-SAFT approach. This study extends the approach to consider all spatial dimensions for silicone to validate the applicability of the model to different polymers. As a result, it is now possible to take all geometric aspects into account when modeling solvent uptake using an equation of state. The extended model shows improved correlations between experimental data and swelling curves compared to the established one-dimensional model. In addition, the Maxwell-Stefan diffusion coefficient was found to be highly susceptible to overestimation when only one dimension is considered. The temperature dependence of the diffusion coefficient was taken into account and, for the first time, the drying of a polymer sample was modeled from the swelling results using the developed model.