Concentration dependence of the microscopic mobility of water in polymer membranes

Introduction Gravimetric vapor sorption provides the means for simultaneous determination of the isothermal concentration of water vapor and the chemical diffusion coefficient given a defined sample geometry such as a polymer film. The present study determines both properties for two polymer packaging films, one of which has undergone treatment to reduce the transmission rate of water. The microscopic (self-) diffusion coefficient is also calculated from these results to show the effect of the treatment on water mobility and to assess how this varies as a function of water content.