The influence of temperature on the sorption process, diffusion process, permeation rate and separation factor of crosslinked chitosan (es) membranes used for the separation of water-ethanol mixtures by pervaporation was investigated. The results indicate the plasticizing effects of the permeants and the interactions among ethanol, water and the polymer on the permeate transport mechanism of Cs pervaporation membranes. The actual swelling profile of EtOH-H2O permeates in multi-layered membranes of various thicknesses were determined. The non-Fickian behaviour of the two component flux and the dependence of the separation factor alpha(H2O/EtOH) on the membrane thickness were analyzed from the experimental data with respect to the formation of craze in the swelling layer.