Exploring the Nature and Origin of Long-range Force between Solvophobic Surfaces in Liquids

2015 Fiscal Year Final Research Report

• Project/Area Number: 25420803
• 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: Ishida Naoyuki 岡山大学, 自然科学研究科, 准教授 (80344133)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 疎水性引力 / 原子間力顕微鏡 / 疎液性引力 / キャビテーション / エントロピー力

Outline of Final Research Achievements

The interaction forces between hydrophobic surfaces in solutions were measured using atomic force microscopy (AFM) to explore the origin of hydrophobic force, a long-range force acting between hydrophobic surfaces in water. In the obtained force curves between the surfaces without nanobubbles, which had been considered the main origin of the force thus far, an attractive force was found from a distance of 10-20 nm. This force is longer-ranged than typical van der Waals attractions, showing that there still is an additional force between hydrophobic surfaces even without nanoubbules. We also conducted the force measurements between the fluorinated silica surfaces in formamide and found an attractive force that is stronger than the van der Waals attraction. This result confirms that the ‘solvophobic attraction’, which is very similar to the hydrophobic attraction, exists in some organic solvents. We suggested a few different origins of the forces depending on the conditions.

Free Research Field

コロイド・界面化学