Effect of Surface Nodular Structure on the PDMS/PES based Membranes Pervaporative Performances in Ethanol / Water Separation

Composite membranes with the same support layer of PES and the active layers based on PDMS with different amount of hydrophobic silica were prepared. Their surface structures were investigated by AFM images. There were nodular structures in the surfaces. Amount of mean nodule sizes were obtained. It wasfound that the mean nodule sizes increased by increasing the percentage of silica in the surfaces. The relation between the surface structure and the pervaporation performance of composite membranes for separation of ethanol from water were then explored. The results showed that by increasing MNS, separation factorincreased but total flux decreased. It may due to the fact that enhancement of MNS increased the membrane effective surface area, therefore the separation performance of the membrane improved