Plasma polymerized membranes for gas separation.

Abstract

A plasma-polymerized thin layer was deposited on the top surface of the skin layer of the asymmetric polyethersulfone Victrex (PES) membrane to plug the ultrafine pores. Aniline was used as the monomer gas of plasma polymerization. Surface characterization by X-ray photoelectron spectroscopy (XPS) measurements has been used to gain insights into the chemistry of plasma-modified membrane surfaces. The steady-state permeation rates for hydrogen, helium, methane, nitrogen, oxygen and carbon dioxide through the asymmetric PES membranes with the plasma modification were measured to evaluate the permeability and the permselectivity. The effect of polyaniline plasma and deposition time on the transport properties of plasma deposits are also discussed. In another set of experiments mixtures of CH$\sb4$/CO$\sb2$ with known compositions were separated using a laminated PES membrane. The modified resistance model was employed to analyze the data of PES membranes laminated with a layer of 1.5 mil silicone unbacked rubber.