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Composite permselective membrane by desposition of an ultrathin coating from a plasma
Author(s) -
Stancell A. F.,
Spencer A. T.
Publication year - 1972
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1972.070160619
Subject(s) - materials science , chemical engineering , hydrogen , composite number , methane , coating , oxide , permeability (electromagnetism) , membrane , solubility , polymer chemistry , composite material , organic chemistry , chemistry , biochemistry , engineering , metallurgy
Permselectivity was vastly improved when ultrathin crosslinked coatings, of the order of 0.5 microns thick, were deposited from a plasma onto relatively permeable film substrates. In one example, the hydrogen‐to‐methane permeability ratio was increased from 0.87 to 33, and the hydrogen permeability was decreased by just 20% when benzonitrile was plasma deposited onto a silicone–carbonate copolymer film. In another example, the hydrogen‐to‐methane permeability ratio was increased to 297 when cyanogen bromide was plasma deposited onto a poly(phenylene oxide) film. Such coatings, while effective for the hydrogen/methane pair, had little effect on modifying film permselectivity for isobutene/butene‐1, a pair nearly identical in molecular size and solubility. It appears therefore that the coatings can very effectively distinguish between molecules differing significantly in size. Also, since the coatings are so thin, the overall permeability of the coating–substrate composite can be high.