An Improved Method for the Preparation of Organic Monolayers of 1-Alkenes on Hydrogen-Terminated Silicon Surfaces

Abstract

The possibility to use dilute alkene solutions for the formation of alkene monolayers with 1-hexadecene on a hydrogen-terminated silicon(100) surface has been investigated for a variety of solvents. The resulting monolayers were analyzed by water contact angles. Anisole, n-butylbenzene, and n-decane were found to be unsuitable solvents for monolayer preparation at all 1-hexadecene concentrations used. At high 1-hexadecene concentrations (25% and 10% (v/v)) well-ordered monolayers were formed in toluene, xylene (mixture of isomers), cumene, tert-butylbenzene, and mesitylene. Only with mesitylene are high-quality monolayers feasible even at significantly lower alkene concentrations (down to 2.5%), making this the solvent of choice. The newly described procedure reduces the amount of alkene needed to form well-ordered monolayers by a factor of 20−40 in comparison with the original procedure that requires neat alkenes.