A new type of colloidal dispersions based on nanoparticles of gelled oil

An original family of colloidal nanoparticles of gelled oil have been prepared as stable dispersions in water. Gelled particles of dicaprylyl ether (oil) and 12-hydroxystearic acid (gelator) were obtained by hot emulsification (T > Tgel), with a surfactant (CTAB) or a polymer (PVA80) as the stabilising agent, and cooling at room temperature (T < Tgel). TEM observation of the dispersion showed spherical particles with a mean diameter of 260 nm, a size in accordance with the DLS. The amount of oil and surfactant controlled the size and the stability of the dispersion. A rheological investigation confirmed the gelled state and the adsorption of the stabilising agent at the surface of the particles. This last point was also proved by zeta potential measurements. A comparative study of the ageing of the emulsion and the corresponding dispersion showed greatly enhanced stability after gelation.