Similarly, a fundamentally opposite behaviour is also observed when adding adsorbing or non-adsorbing polymer chains, respectively, to a microemulsion system. Ionic surfactants with multivalent counterions. Electrostatic effects dominate the phase equilibria of ionic surfactant systems. Presently, we are investigating specific ion effects on the phase behaviour and microstructure in two and three component systems with surfactants of the didodecyldimethylammonium type. The general properties of these systems are found to be drastically dependent on the type of counterion used.
Divalent surfactants are important from a technical point of view.
They are, for example, used as stabilisers for asphalt emulsions and for disinfection. They are also interesting from a more fundamental point of view since a full understanding of the factors that govern self-association and other properties of charged surfactants in water and other polar solvents require a deep insight into the electrostatic interactions. In this regard divalent surfactants constitute a good test case for electrostatic models. In this project divalent surfactants with monovalent counterions are studied with respect to the CMC, the micellization process and the complete phase diagram. Moreover, present electrostatic theories for surfactant systems have been applied and shown to satisfactorily explain the experimental results.