Effect of Electrolyte and Alcohol in Solution on the Hydrophobic Attraction between Alkoxylated Silica Surfaces

The interaction forces between silica surfaces when nanobubbles were removed from the surfaces were measured using an atomic force microscope. In the approaching force curves between the hydrophobic surfaces, an attractive force was observed from a distance of 10-20 nm. The electrolyte concentration had little effect on the range and strength of the interaction, whereas the addition of even a small amount of ethanol dramatically reduced the range of the interaction.