Temperature-insensitive microemulsions and dilution ripening

Abstract

Single-phase microemulsions are thermodynamically stable dispersions of an oil in water (O/W) or water in oil (W/O) and are an attractive means of formulating agrochemical products (bicontinuous systems of mutually dispersed oil and water are also possible). Two areas of interest are reported in this summary. (i) Temperature sensitivity – a disadvantage of many microemulsion systems is that the phase boundary of the single-phase region is often highly dependent upon temperature and electrolyte concentration. The aim of this work was the production of temperature-insensitive systems, the criterion used being that the radius of curvature of the droplets at the solubilisation boundary was independent of temperature. (ii) The application of microemulsion systems will involve dilution into water to form the spray system and, as such, an understanding of how the droplets grow under these conditions is of importance. Factors affecting droplet growth processes occurring upon dilution into water have been investigated.