Water diffusion in polymer coatings containing water-trapping particles. Part 1. Finite difference-based simulations

作者：Tabor Zbislaw; Krzak Malgorzata; Nowak Pawel; Warszynski Piotr^*

来源：Progress in Organic Coatings, 2012, 75(3): 200-206.

DOI：10.1016/j.porgcoat.2012.04.018

• Kalnin%26apos
• s model
• Nanotraps
• Composite coatings
• Diffusion in polymers

Systematic finite-difference study of the effective diffusivity in 2D and 3D composites is reported. The dispersed phase consists of squares (2D) or cubes (3D) randomly scattered within the host phase. The study is focused on the case of practical significance, where the volume fraction of the dispersed phase (inclusions) is below the percolation threshold. The concentration of diffusing species is monitored as the function of time and an effective coefficient of diffusion is derived, based on an analytical formula for a homogeneous medium. It is shown that the dependence of the numerically found effective coefficient of diffusion upon the diffusivities of the two phases, volume fraction of the dispersed phase, dimensionality of the system and the ratio of equilibrium concentration of the diffusing species in the dispersed and in the host phases agrees very well with analytical predictions. The process of diffusion in sandwich-structured films, containing layers with varied volume fraction of inclusions, is also considered and an effective 1D approach is proposed to model this type of systems.

• 出版日期2012-11