Polyaniline (PANi) was synthesized by oxidative polymerization and doped with poly(acrylic acid) (PAAc) for pervaporation of aqueous isopropanol. PANi membranes were prepared by solution blending with N-methyl pyrrolidone (NMP) and exhibited the high oxidation stability enough to adopt as dehydration membranes. The conformational hindrance and bulkiness of PAAc chains caused PANi membranes disordered structures. The d-spacings of PANi/PAAc indicated a strong interaction between these two polymers by complexation. When the content of PAAc in doped membrane was 20 wt%, water concentration in permeate decreased to 97 wt%, while permeate flux increased to ca. 200 g/m(2) h due to the affinity of PAAc toward water. Water flux of PANi/PAAc membrane increased with PAAc mixing ratio of up to 30 wt%. Membranes containing more than 30 wt% PAAc showed the analogous results that flux and water concentration in permeate were about 300 g/m(2) h and similar to 100 wt%, respectively. Permeate flux through PANi/PAAc membrane decreased with increasing feed IPA concentration while water concentration in permeate was maintained to be over 85 wt%. Water concentration in permeate was much higher than IPA concentration because of high affinity of PANi complex membrane toward water molecules. The activation energy for permeation from an Arrhenius-type expression was ca. 50 KJ/mol.