Heterogemini surfactants

Heterogemini surfactants are geminis with different types of polar head groups. This review presents a number of different heterogemini surfactants that have been reported in literature. It was shown that surfactants of this type behave mainly as normal surfactants, with similar sequences of phases and aggregate structures, but they also show interesting differences. They exhibit some unusual physicochemical properties that might prove useful for technical applications in the future. Their strong tendency to self-associate at very low concentration and their ability to pack at interfaces make heterogemini surfactants interesting candidates for applications where ease of micelle formation and efficiency in reducing surface tension and adsorbing at interfaces are important. The following aspects of these surfactants have been successively reported: the synthesis route, the aggregation behavior in aqueous solutions, the adsorption at the air-water and solid-water interfaces, the micelle microstructure and micelle dynamics. (C) 2002 Elsevier Science B.V. All rights reserved.