Water vapor diffusion in polyurethane silica nano-composite

Diffusion of water vapor in polyurethane silica nano-composite membrane was found by experiment and MD simulation. Water vapor molecules diffuse through the free volume created in the polymer matrix after the addition of silica nano-particles. Different surface modifiers were used for the silica nano-particles. The modified surface silica nano-particles containing hydroxyl groups enhance the diffusion of water vapor molecules due to the hydrogen bonding created with water vapor molecules. Water vapor permeability is measured experimentally by the ASTM standard E-96 and compared to the simulation results.