Several hydrophilic membranes were prepared by solvent casting from filled copolymers. These filled copolymers were synthesized by free radical polymerization of acrylonitrile (AN) and N-vinylpyrrolidone (NVP) monomers in different comonomer ratios (AN/NVP) in the presence of a nanosized clay. The membrane polymers were analyzed by NMR, Fourier transform infrared spectroscopy, X-ray diffraction, differential thermal and thermogravimetric analyses, scanning electron microscopy, mechanical properties, and dynamic mechanical analysis for characterization of its structural configuration, functionalities, copolymer composition, distribution of clay in the copolymer, and the strength and stability of the membrane under dynamic and thermal stress. The sorption and pervaporation of acetonitrile water-mixtures through these membranes were studied at varied copolymer compositions, mass % of clay, feed concentrations of water, and feed temperatures. Sorption data were analyzed by binary and ternary solvent/membrane interaction parameters while the diffusion coefficient of solvents through the membranes was determined by a solution-diffusion model. The synthesis and process variables were optimized by a central composite design of the response surface methodology with flux and separation factor as output responses. The membrane prepared with the AN/NVP mole ratio of 12:1 and 1 mass % nanoclay showed the optimized flux and separation factor of 160 g/m(2) h and 196, respectively for 90 mass % acetonitrile in feed which was dehydrated to 95.6 mass % after pervaporation. The long-term stability of the membrane was also evaluated. Comparison of tensile properties of unused and used membranes confirmed mechanical stability of the membrane while FTIR analysis revealed that there was no change in structure or composition of the membrane after prolonged use.