DEPLETION INTERACTIONS AND FRACTIONATED CRYSTALLIZATION FOR POLYDISPERSE EMULSION PURIFICATION

By analogy with fractionated crystallization applied to atomic or molecular liquid mixtures, a purification method is proposed based on the liquid-solid colloidal phase transition induced by attractive depletion interactions, which are very sensitive to particle size. If one repeats the demixing of the liquid and the solid phases several times, it is possible to separate more and more precisely bigger particles which solidify from smaller ones (which remain in the liquid phase). This method leads finally to a set of monodisperse samples which exhibit iridescence. This purification method can greatly extend the variety of monodisperse suspensions available. © 1991.