Membranes have been fabricated from organic-based TiO2 sols via a coating process. This process produces an essentially flaw-free membrane. Gas permeability experiments employing these membranes indicate that these membranes possess unique properties. These membranes exhibit relatively high permeabilities to propylene at low pressures. This property of these membranes can be attributed to a mechanism involving some form of condensed phase transport. The data also indicate that transport of helium, oxygen and nitrogen involves, to some extent, a form of surface transport.