Formation of Tubules by a Polymerizable Surfactant

Abstract

The 1, 2-bis(10, 12-tricosadiynoyl)-sn-glycero-3-phosphocholine, in which both fatty acyl chains contain polymerizable diacetylenic units, has been studied with regard to its behavior in aqueous dispersion before and after polymerization. The monomeric lipid may be dispersed in distilled water above its chain melting transition temperature, but, contrary to previous reports, it does not stay in liposomal form on subsequent reduction of the temperature. Microscopic observation shows formation of structures resembling so-called cochleate cylinders, except that these cylinders are water-filled. These "tubules" reversibly convert to liposomal form on heating above the monomer chain melting temperature. However, on polymerization with ultraviolet light, the cylinders are “locked in” and no morphological changes are observed on heating. These unique structures may represent a new class of orientable polymers.