Oxygen permeability of surfactant/polymer composite films with multibilayer and inverted hexagonal structure

Abstract

AbstractThe permeability of oxygen through horizontally oriented multibilayer films of polyion complexes prepared from quaternary ammonium‐type surfactants [CH3(CH2)n‐1]2N+(CH3)2Br−(n = 14, 16, 18), and poly(p‐styrenesulfonate) or poly[2‐(acrylamido)‐2‐methyl‐1‐propanesulfonate], was measured in water using an oxygen electrode. The permeability depended mainly on the phase of the multibilayers. Thus, it increased abruptly (about 10‐fold) near each phase transition temperature because of the fluidity enhancement of the multibilayer. Inverted hexagonal type nonbilayer films prepared from the polyion complexes and cholesterol had greater permeability (2–20‐fold) than the multibilayer films in both phases. The large permeability of the nonbilayer films was attributed to the lack of a barrier such as the bilayer and lower crystallinity of the films. It was associated neither with an increase in thermal movement of the lipid surfactant molecules nor with an increase in the water content of the films by the addition of cholesterol. © 1993 John Wiley & Sons, Inc.