Solvent permeation behavior of PDMS grafted γ-alumina membranes

Solvent permeability in polymer grafted ceramic membranes was described by incorporating solvent sorption terms into the Hagen-Poiseuille equation. Two types of ceramic membranes grafted with a relative short or long PDMS chain (n=10 and n=39), which differed in pore size, were examined. Sorption was measured “ex situ” using a pure PDMS phase. The results show that curves of flux versus transmembrane pressure were identical for all solvents studied if flux values are corrected for viscosity as well as sorption of the solvent. It is suggested that the permeable volume of the membrane reduces by swelling of the grafted organic moiety by the solvent used. This model provides a way to predict the performance of grafted porous membranes for solvent filtration.