EFFECT OF ACRYLAMIDE AND DODECANE ON THE PHASE-BEHAVIOR OF MONOOLEIN

Lipids when dissolved in water have been shown to self-assemble and fo rm a broad spectrum of complex microstructures which include isotropic micellar and microemulsion phases and liquid crystalline lamellar, he xagonal, and bicontinuous cubic phases. The phase behavior of the mono olein-water system as a function of a polymerizable monomer (acrylamid e) and an oil (dodecane) was studied. It is found that with increasing acrylamide concentration, the cubic phases of monoolein are destabili zed and replaced by the lamellar phase. This effect was then reversed by adding dodecane to the system. The observed behavior is explained u sing the surfactant parameter alpha = v/al. It is found that acrylamid e interacts with the monoolein head group and increases the head group area a (smaller alpha), while dodecane partitions between the hydroph obic tails and increases the values of v/l and alpha, thus reversing t he effects of acrylamide.