Properties of water-in-oil (W/O) nano-emulsions prepared by a low-energy emulsification method

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 324; no. 1; pp. 181 - 188
• Main Authors: Porras, M., Solans, C., González, C., Gutiérrez, J.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2008; Elsevier
• Subjects: Chemistry; Colloidal state and disperse state; Emulsions. Microemulsions. Foams; Exact sciences and technology; General and physical chemistry; Low-energy emulsification method; Mixed non-ionic surfactant; Span/Tween; Surface physical chemistry; W/O nano-emulsion; W/O nano-emulsion; Span/Tween; Mixed non-ionic surfactant; Low-energy emulsification method; Water; Emulsion; Oil; Energy; Emulsification; Non ionic surfactant
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2008.04.012

Properties of water-in-oil (W/O) nano-emulsion formed by a low-energy emulsification method are described in this work. Nano-emulsions have been formed in water/mixed non-ionic surfactant/decane. Several mixtures of Span 20, Span 80, Tween 20 and Tween 80 were studied. Phase behavior studies and stability studies allowed to determine zones where nano-emulsions can be formed. Bluish and transparent W/O nano-emulsion with droplet sizes as low as 30 nm was formed. Nano-emulsion droplet size was measured by Dynamic Light Scattering. Nano-emulsions stability was studied by multiple light scattering and by dynamic light scattering. The results showed the evolution with time of the average radius droplet. The nano-emulsions prepared showed high kinetic stability for weeks, without phase separation, sedimentation or creaming. Nevertheless, their droplet size increased slightly over time. Stability studies show that nano-emulsion breakdown could be attributed to Ostwald ripening and coalescence mechanism, depending on the water concentration.