Ethanol macrocluster formation on Au substrate modified with self-assembled monolayers bearing hydrogen-bonded functional groups

We have revealed that the ethanol macrocluster whose thickness is ca. 5-6 nm is formed on the gold substrate modified with mercapto compounds bearing hydrogen-bonding functional groups, namely, OH and COOH groups. This study aims at examining the effect of the surface densities of SAMs bearing the hydrogen-bonding functional groups on the ethanol adsorption layer. We prepared the SAMs of the 11-Mercaptoundecanol mixed with the n-Octyl Mercaptan. With increasing the surface density of the OH group, the thickness of the ethanol adsorption layer increases from ca. 0.5 nm thickness at 0% to ca. 5.5 nm thickness at 100%. As a result, we can control the thickness of the ethanol adsorption layer by changing the surface density of OH group.