OSTWALD RIPENING OF CONCENTRATED ALCANE EMULSIONS

The kinetics of ageing processes in emulsions of n - alcanes stabilise d by a surfactant is studied by dynamic light scattering (DLS). Experi mental results show that the main ageing process is Ostwald ripening. The results are in agreement with theoretical predictions based on the Lifshitz - Slyozov - Wagner (LSW) theory. In particular the predicted relation between the molecular solubility of the n-alcanes (in the aq ueous phase) and the Ostwald ripening rate is verified. This illustrat es that the main rate determining factor is the molecular diffusion of the alcane molecules through the continuous (aqueous) phase. The Ostw ald ripening is affected by the alcane concentration, however hardly b y the concentration of surfactant; it is about a factor two higher tha n expected from LSW-theory for dilute systems.