Organic-inorganic cation exchange hybrid membranes have been prepared through sol-gel reaction of poly(acrylic acid-co-methacryloxypropyl trimethoxy silane (poly(AA-co-gamma-MPS)) in presence of poly(vinyl alcohol) (PVA). The membranes are characterized by FTIR, SEM, thermal stability and mechanical strength. T(d) values are in the range of 264-270 degrees C. TS ranges from 8.4 MPa to 32.2 MPa and E(b) in the range of 72.1-103.5%. The membranes can remain integrity in 65 degrees C hot water for more than 12 days and the swelling behavior is better suppressed as poly(AA-co-gamma-MPS) content increases. The membranes are tested for recovering sodium hydroxide from the mixture of sodium hydroxide (NaOH) and sodium tungstate (Na(2)WO(4)) at different temperatures (35-55 degrees C) through diffusion dialysis (DD). Both permeability and selectivity are excellent despite the low IEC of the membranes and the low diffusivity of OH ions. The dialysis coefficients of OH(-) (U(OH)) are in the range of 0.010-0.042 m/h, similar to previously reported values for acids (U(H): 0.005-0.055 m/h). The hybrid membrane containing 50 wt% poly(AA-co-gamma-MPS) has the highest separation factor of 95.7 at 35 degrees C. The DD performances have been correlated with the membrane physico-chemical structure, especially the presence of large amount of -OH groups. (C) 2011 Elsevier B.V. All rights reserved.