Conjugated Polymer Films for Gas Separations

Publisher Website
Google Scholar
Abstract
Permeabilities for a series of gases through free-standing films of the conjugated polymer polyaniline are reported. A remarkable selectivity has been achieved for important gas pairs incuding hydrogen-nitrogen, oxygen-nitrogen, and carbon dioxide-methane. The selectivity values of 3590 for H2/N2, 30 for O2/N2, and 336 for CO2/CH4 surpass the highest previously reported values of 313, 16, and 60 for the nonconjugated polymers poly(trifluorochloroethylene), cellulose nitrate, and a fluorinated polyimide, respectively. The process for tailoring gas selectivity of a polyaniline membrane involves first enhancing the permeabilities of gases with small diameters [3.5 Å diameter) through controlled redoping of the polymer. The permanent morphological changes induced in this conjugated polymer system and others indicate the potential for development of universal membranes for gas separations.