Adhesion between silica surfaces due to hydrogen bonding

• Published in: Surface topography metrology and properties Vol. 4; no. 3; pp. 34001 - 34005
• Main Authors: Bowen, James, Rossetto, Hebert L, Kendall, Kevin
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.09.2016
• Subjects: adhesion; atomic force microscopy; dimethylformamide; ethanol; formamide; silica; water
• ISSN: 2051-672X; 2051-672X
• DOI: 10.1088/2051-672X/4/3/034001

The adhesion between surfaces can be enhanced significantly by the presence of hydrogen bonding. Confined water at the nanoscale can display behaviour remarkably different to bulk water due to the formation of hydrogen bonds between two surfaces. In this work we investigate the role of confined water on the interaction between hydrophilic surfaces, specifically the effect of organic contaminants in the aqueous phase, by measuring the peak adhesive force and the work of adhesion. Atomic force microscope cantilevers presenting hemispherical silica tips were interacted with planar single crystals of silica in the presence of dimethylformamide, ethanol, and formamide; solution compositions in the range 0-100 mol% water were investigated for each molecule. Each molecule was chosen for its ability to hydrogen bond with water molecules, with increasing concentrations likely to disrupt the structure of surface-bound water layers. With the exception of aqueous solutions containing low concentrations of ethanol, all molecules decreased the ability of confined water to enhance the adhesion between the silica surfaces in excess of the predicted theoretical adhesion due to van der Waals forces. The conclusion was that adhesion depends strongly on the formation of a hydrogen-bonding network within the water layers confined between the silica surfaces.