Measurement of apparent diffusion constant on the cross‐section of thin PVA films under a free swelling condition with a facile electronic device.

The importance of predicting the diffusion coefficient to describe the diffusion process in glassy polymers is obvious. However, most of the direct measurements of diffusion coefficients are time‐consuming, expensive and system intrusive. Here, we report a facile method to measure the apparent diffusion constant on the cross‐section of thin PVA film with a device that is structured with a thin conductive film. The results can employ diffusion and the solution conductivity theory well. The diffusion time and the conductivity of the device are determined by the process of solution passing through the cross‐section of thin PVA film and reaching the conductive substrate. The data detected the apparent diffusion constant in diffusion and the concentration gradient of the solution on the interface between the PVA film and conductive film. This device provides a simple, rapid, and effective way to study the apparent diffusion constant in PVA film. It holds great potential in predicting the diffusion process of a thin glassy polymer film. [ABSTRACT FROM AUTHOR]