Stabilization of oil-water interface by screening effect with counterion

2015 Fiscal Year Final Research Report

• Project/Area Number: 25420802
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Properties in chemical engineering process/Transfer operation/Unit operation
• Research Institution: Okayama University
• Principal Investigator: Oshitani Jun 岡山大学, 自然科学研究科, 准教授 (70314656)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: Screening効果

Outline of Final Research Achievements

Stabilization of oil-water interface by screening effect with counterion was investigated in this study. The stabilization was evaluated using O/W emulsion by changing the surfactant concentration with addition of various salts. It was found that the stabilization is dependent on the kind of counterion; the hydration of the counterion relates to the stability. The stability of surfactant-free O/W emulsion was also evaluated based on the screening effect with proton by changing pH. Stable emulsion is formed at high pH without using the surfactant, but phase separation is remarkable at low pH. The low stability at low pH is caused by the fact that large amount of proton enhances the screening effect, which results in that the surface charge is reduced and electrostatic repulsion between the oil droplets is also reduced. The microscopic effect on the stability of emulsion was clarified by this research. These results will contribute to manufacturing of colloidal products.

Free Research Field

コロイド化学工学