Preferential adsorption followed by spontaneous desorption of 1-octadecanol at a solution/graphite interface

The dynamical behavior of adsorption/desorption of 1-octadecanol on graphite was investigated by scanning tunneling microscopy under the existence of 3-imino-4,5,6,7-tetrachloroisoindolin-1-one (ITCH) in a 1-phenyloctane solution. The monolayer of 1-octadecanol was first formed preferentially, as it was the rich component, with many domains at the solution/graphite interface. The molecules at the domain boundaries were then spontaneously replaced by the ITCH molecules, keeping the hydrogen bonding of the OH head groups of 1-octadecanol. The driving force of this replacement can be explained by the difference in heats of adsorption per unit area between those two molecules. (C) 2010 Elsevier B.V. All rights reserved.