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A novel and facile layer-by-layer (LbL) selfassembly?process driven by hydrophobic interaction and then
reinforced by hydrogen bond was developed to prepare ultrathin?membranes. Gelatin (GE) and tannic acid (TA) were alternately?deposited on polyacrylonitrile (PAN) ultrafiltration membranes?to obtain GE/TA membranes. The required number of?deposition cycles for acceptable permselectivity of membrane?was greatly reduced compared with that of the traditional LbL?self-assembly process and could be ascribed to the rapid growth?of membrane thickness and the integrity of the innermost gelatin?layer. Higher surface hydrophilicity and more appropriate free volume characteristics were obtained for GE/TA multilayer?membranes compared with pristine gelatin membrane. Moreover, the GE/TA multilayer membrane exhibited improved stability?even at high water content of 30 wt %. The membrane separation experiments with pervaporation dehydration of ethanol?aqueous solution as a model system demonstrated the GE/TA multilayer membrane achieved higher water permselectivity than?the pristine gelatin membrane. High operation stability was acquired in the long-term membrane separation test.