Solidification of stearic acid—water and laurone—water emulsions: Role of the droplet—medium interface on nucleation kinetics

• Published in: Journal of colloid and interface science 1986-02, Vol.109 (2), p.542-551
• Main Authors: Grange, G, Lévis, A, Mutaftschiev, B
• Format: Article
• Language: English
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/0021-9797(86)90335-8

The nucleation of two emulsified organic substances, an acid (stearic acid) and a ketone (laurone), has been studied by determining the critical undercoolings. To explain their different behavior, the interfacial tensions and contact angles, which can influence energetically the nucleation, have been experimentally determined. The conclusion is that the nucleation is induced by the droplet surface for both materials, for the used emulsifier concentration; but the adsorption is quite different. The layer adsorbed on the surface of the acid droplets is a complex mesomorphic phase composed of acid, water, and surfactant. For laurone, the invariability of the undercooling with two different emulsifiers can be explained by the weak adsorption and by identical interfacial tensions in both cases. A very simple model of crystal nucleus allowed to discuss the different possible cases of nucleation depending upon the variation of the three interfacial tensions involved in that nucleation phenomenon.