Water Droplet Coalescence Rates in Water-in-Oil Microemulsions

Abstract

We have measured the water droplet coalescence rates of water-in-oil (W/O) microemulsions stabilised by mixtures of dodecyltrimethylammonium chloride (DTAC) and butanol. The second order rate constants are close to the diffusion controlled limit and are three to four orders of magnitude greater than the rates for similar sized water droplets stabilised by sodium bis-2-ethylhexylsulphosuccinate (AOT). The differences between the two systems are discussed in terms of the energies required to bend and compress the different surfactant monolayer films.