A Vycor (R) membrane with reduced size surface pores I. Preparation and characterization

Vycor(R) membranes are surface-modified by a crosslinked commercial silicon e which is subsequently subjected to oxygen plasma and converted to silica dioxide. Samples are examined by integral gas permeability of helium, nitro gen, methane and carbon dioxide, differential permeability of carbon dioxid e and relative permeability of helium gas vs. water vapor. The modified sur face Is found to contain large micropores as well as a population of small nanopores. The new membrane may be appropriate for applications such as gas /vapor separations, reverse osmosis and the low molecular weight end of nan ofiltration.