A comprehensive study was performed on a new application of thin film composite membranes and selecting a stable sublayer for them as pervaporation membranes in organic solvent separation. For this purpose, four different polymeric sublayers of polyethersulfone (PES), cellulose acetate, polyacrylonitrile, and polyetherimide were prepared, and the interaction of methanol (MeOH) and methyl tert butyl ether (MTBE) with them was investigated. The contact angle results, scanning electron microscopy images, and swelling and mechanical strength measurements obviously displayed the effect of immersion in organic solvents on the sublayers. Finally, a polyamide active layer was subsequently deposited on the PES membrane surface as the stable sublayer via interfacial polymerization based on a multistep statistical optimization strategy involving fractional factorial design and a response surface method. The prepared TFC membranes were tested in the pervaporation of a MeOH/MTBE mixture and exhibited excellent performance compared with the current membranes in this context.

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