POLYMERIZATION IN MICROEMULSIONS .1. FORMULATION AND STRUCTURAL-PROPERTIES OF MICROEMULSIONS CONTAINING A CATIONIC MONOMER

The formulation of microemulsions containing methacryloyloxyethyltrimethylammonium chloride for purposes of polymerization has been investigated. By using cohesive energy ratio hydrophile-lipophite balance concepts, general rules of selection for a good chemical match between oils and nonionic surfactants have been established. The cationic water-soluble monomer plays an important role in the formulation, owing to its amphiphilic and electrolytic character, as confirmed by surface tension and turbidimetry experiments. As a cosurfactant, it enhances considerably the microemulsion domain and as an electrolyte, it salts-out the surfactant. These effects taken together control the structural properties of the microemulsions. The optimal conditions correspond to bicontinuous microemulsion which form in an HLB range (12-13) higher than would be expected in the balance of monomer. © 1990.