On the nature of colloidal aphrons

Abstract Colloidal gas (liquid) aphrons (CGAs/CLAs) were originally proposed by professor Sebba to be unique and intriguing systems with structure different from general foams or emulsions. As a consequence of their fascinating colloidal properties, a number of investigators have exploited various industrial applications. However, the nature especially the interfacial structure of this colloidal dispersion is still disputed by many researchers. Here we demonstrate the differences and similarities between colloidal aphrons and common foams/emulsions in terms of their formulation and formation, interfacial structure, stabilization and stability. Theoretical and experimental evidence indicates that the colloidal system described by Sebba is indeed identical to conventional foams or emulsions, and therefore, the specific term “aphrons” should be abandoned to eliminate current confusion. These findings are important for understanding the concepts and principles of gas/liquid and liquid/liquid dispersion systems, and would also be helpful for their wide applications.