ABSTRACT
This chapter, which is focused on investigations carried out at the Max Planck Institute for Colloidal and Interfacial Studies in Berlin, begins with the synthesis and discusses the interfacial behavior of quaternary ammonium groups containing siloxane surfactants. It describes new directions of the development of siloxane surfactants. Most of the siloxane surfactants used in different fields of industrial application are mixtures of polydimethylsiloxanes with or without functional groups, which consist of compounds with a distribution of molecular weight and/or of isomers. One step in the synthesis of siloxane surfactants is in most cases the hydrosilylation of unsaturated compounds: that is, the addition of a silicon hydride group to a double or triple bond, catalyzed by hexachloroplatinic acid in isopropanol or other metal compounds. The investigation of crystalline siloxane surfactants offers the opportunity to compare x-ray crystal structure data with surface activity measurements.
