Liquid Crystalline Phases and Emulsifying Properties of Block Copolymer Hydrophobic Aliphatic and Hydrophilic Peptidic Chains

Abstract

Amphiphilic lipopeptides with a hydrophobic paraffinic chain containing from 12 to 18 carbon atoms and a hydrophilic peptidic chain exhibit lyotropic mesophases and good emulsifying properties. The X-ray diffraction study of the mesophases and of dry lipopeptides showed the existence of three types of mesomorphic structures : lamellar, cylindrical hexagonal and body-centred cubic. Two types of polymorphism were also identified : one as a function of the length of the peptidic chain and the other as a function of the water content of the mesophases. The emulsifying properties of the lipopeptides in numerous pairs of immiscible liquids such as water/ hydrocarbons and water/base products of the cosmetic industry showed that small amounts of lipopeptides easily give three types of emulsions : simple emulsions, miniemulsions and microemulsions.