Cast Multibilayer Films from Polymerizable Lipids

Polymeric cast multibilayer films were prepared from a variety of polymerizable lipids according to two different procedures. One of these procedures is to polymerize the vesicle suspension first and then cast the film. The second procedure is to cast a film from a monomeric aqueous dispersion and then polymerize the cast film after it has been dried. The structure of these films was determined by different methods. Films from dioctadecyldimethylammonium acrylate were investigated in more detail. In films prepared according to the second procedure the lipids were oriented in multibilayer structures to a much higher degree than in films prepared from polymerized vesicles as wide-angle X-ray scattering revealed. Also, films that were polymerized after casting did not swell but remained stable in electrolyte solution. These films may thus be suitable for use in reverse-osmosis membranes. Their suitability for gas separation membranes was also tested, and the gas permeation was found to be dependent only on the molecular weight of the gas.