Dry oil powders and oil foams stabilised by fluorinated clay platelet particlesElectronic supplementary information (ESI) available. See DOI: 10.1039/c3sm52748d

• Main Authors: Binks, Bernard P, Sekine, Tomoko, Tyowua, Andrew T
• Format: Article
• Language: English
• ISSN: 1744-683X; 1744-6848
• DOI: 10.1039/c3sm52748d

A series of platelet sericite particles coated to different extents with a fluorinating agent has been characterised and their behaviour in mixtures with air and oil studied. The material which forms by vigorous shaking depends on both the surface tension of the oil and the surface energy of the particles which control their degree of wetting. Oil dispersions are formed in liquids of relatively low tension ( 70°, we have discovered that dry oil powders in which oil drops stabilised by particles dispersed in air (oil-in-air) can be prepared by gentle mixing up to a critical oil : particle ratio (COPR) and do not leak oil. These powders, containing up to 80 wt% oil, release the encapsulated oil when sheared on a substrate. For many of the systems forming oil powders, stable liquid oil marbles can also be prepared. Above the COPR, catastrophic phase inversion occurs yielding an ultra-stable air-in-oil foam. We thus demonstrate the ability to disperse oil drops or air bubbles coated with particles within novel materials. Powdered oil (oil-in-air) and oil foam (air-in-oil) contain liquid interfaces coated with suitably treated clay platelet particles.