Adsorption Of Oleate On Fluorite Surface As Revealed By Atomic Force Microscopy

The adsorption of oleic acid/oleate on fluorite surface Could be Visualized using tapping mode of atomic force microscopy (AFM). The natural fluorite crystals were equilibrated with 10(-3) to 10(-7) M oleate solutions and their AFM images at each concentration along with height profiles were recorded. Even at low oleate concentration of 1 x 10(-7) M, concomitant monolayer and bilayer structures were observed. It suggests that normal-normal bonding of hydrocarbon chains takes place before the surface is completely covered by the monolayer. Multi-layer adsorption of oleate was observed at oleate concentrations of above 10(-4) M. The tapping mode AFM can be utilized to visualize the topography of surfaces adsorbed with surfactant Molecules. (C) 2008 Elsevier B.V. All rights reserved