WATER IN FLUOROCARBON GEL EMULSIONS - STRUCTURES AND RHEOLOGY

New highly concentrated emulsions have been prepared from fluorocarbon and non-ionic fluorinated surfactants. They can contain up to 98% water as the dispersed phase and may be quite transparent. With such a water content, they behave like viscoelastic materials (gels). The continuous phase is a water-swollen micellar phase, whose structure has been investigated by small-angle X-ray and neutron scattering. An attempt at a correlation between this continuous phase and the phase diagram shows that it could be in a surfusion state. Systematic determinations of the specific area of the emulsions have been performed (X-ray and neutron scattering), and the results are compared to those from optical microscope observations, the parameters of interest being the composition, temperature and concentration of additives. The theological behaviour is discussed in terms of spectra of retardation/relaxation times, and the yield stresses are obtained in several ways. The applicability of Princen's equation is discussed briefly.