Blended Poly (vinyl alcohol)-Chitosan membranes were prepared and characterized using Atomic Force Microscopy (AFM) to study the physiochemical structure of the membranes and their effect on pervaporation.. Tapping mode AFM surface scans showed that the membrane surfaces were rough on a nanometer scale. Water contact angle measurements were also performed to determine the surface hydrophilicity of the membranes. Compared to non-crosslinked membranes, the crosslinked membranes were shown to change in chemical structure by FTIR and become less hydrophilic by water contact angle measurement. Hydrophilicity of the blended membranes did not change significantly compared to pure poly (vinyl alcohol) membrane or pure Chitosan membrane. Dehydration of isopropanol-water mixtures were conducted over a range of isopropanol concentrations (40-95 wt%) in the feed solution. The present study shows that compared to the total flux, the selectivity is significantly affected by the blending of the two polymers. The physiochemical results were then quantitavely correlated to the separation performance.