Long range attraction between glass surfaces in cyclohexane-ethanol binary liquids

Interaction forces between glass surfaces in cyclohexane-ethanol binary mixtures were investigated using colloidal probe atomic force microscopy. An unusually long range attraction was found in the presence of ethanol in the concentration range of 0.1 similar to 1.4 mol%. At 0.1 mol% ethanol, the attraction appeared at a distance of 35 +/- 3 nm and turned into a repulsive force below 3.5 +/- 1.5 nm upon compression. A possible explanation accounting for this long range attraction is the bridging of opposed adsorption layers of ethanol on the glass surfaces.