Abstract
Abstract The diffusivity and permeability characterizing transport in poly(α-amino acid) membranes have been determined for helium, hydrogen, argon, oxygen, nitrogen and carbon dioxide in the temperature range 10 to 60°C. The membranes of six poly(α-amino acid)s, namely poly(L-leucine)(PLL), poly(γ-methyl-L-glutamate)(PMLG), poly(L-methionine) (PMt), poly(γ-benzyl-L-glutamate)(PBLG), poly(N∈-carbobenzoxy-L-lysine)(PLy-Z) and poly(γ-L-glutamic acid) (PG) were synthesized. In order to elucidate the effect of the side chain on transport, membranes were used whose polymer main chain is a rigid α-helical structure. The side chains have a great influence on transport properties; for example, the permeabilities of nitrogen were distributed in the range 2 x 10 -10 to 1 x 10 −14cm3 (STP)cm/cm2-sec-cmHg at 20°C for PLL and PG, respectively. The ratio of the permeability coefficients of hydrogen and nitrogen was considered to be a measure of the degree of compactness between helices of poly(α-amino acid) membranes. Anomalous transient state permeation curves were observed for nitrogen in PG. The Arrhenius plots of diffusivity for various gases in the polymer with the largest side chain (PLy-Z) show an inflection and are concave to the reciprocal temperature axis.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call