Aqueous foams stabilized with particles and nonionic surfactants

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2008-07, Vol.324 (1), p.1-8
• Main Authors: Zhang, Shuiyan, Sun, Dejun, Dong, Xiaoqiang, Li, Caifu, Xu, Jian
• Format: Article
• Language: English
• Subjects: Adsorption; Chemistry; Colloidal state and disperse state; Emulsions. Microemulsions. Foams; Exact sciences and technology; Foam stability; General and physical chemistry; Nonionic surfactant; Particle; Surface physical chemistry
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2008.03.020

The aqueous foams prepared by mixtures of Laponite particle and nonionic surfactant (C 12E 4, tetraethylene glycol monododecyl ether) were studied in detail. A synergistic effect on foam stability occurs and becomes more obvious with increasing C 12E 4 concentration. The synergistic effect mainly comes from the adsorption of particles on the bubble surface and the formation of a three-dimensional network in the coherent phase. The enhancement of the synergistic effect is attributed to the increased adsorption density of the particles. In addition, foams prepared by silica/C 12E 4 and Laponite/C 12E 23 dispersions were compared with Laponite/C 12E 4 foams for better understanding. For silica/C 12E 4 dispersions, the synergistic effect on foam stability is found at high surfactant concentrations and just results from the increased viscosity of the dispersions. No silica particles are adsorbed at the air–water interface within the synergistic range. For Laponite/C 12E 23 dispersions, no synergistic effect on foam stability is found. The modified Laponite particles cannot be adsorbed on the bubble surface because of their hydrophilicity. It is assumed that the differences in the foam stability of the three systems arise from the different adsorption of surfactants on the particles.