On certain solved and unsolved problems with water/PDMS/surfactant systems.

Most of the properties of the polydimethylsiloxane (PDMS) oils can be deduced from the structure of the linear polymeric chain of the macromolecule, including flexibility and stability of the Si-O-Si backbone, and hydrophobicity of the methyl substituents of the silicon atom. But in fact, the advantages of pure PDMS for industrial application are limited. For the major uses, it is always necessary to either disperse variable amounts of silica in PDMS or to emulsify PDMS in water. The interfacial properties of the water/PDMS/surfactant system were therefore investigated according to phase diagrams, surface tension, and ellipsometric measurements (carried out at CNRS Monpellier), and x-ray and ESR measurements (carried out at Collège de France, Paris). The relationship between the amphiphilic behavior of the PDMS chain and the practical advantages of the PDMS/water system will be discussed. [ABSTRACT FROM AUTHOR]