Formation and characterization of a highly ordered and well-anchored alkylsilane monolayer on mica by self-assembly

A close-packed, well-ordered monolayer can be formed on a freshly cleaved muscovite mica surface by allowing hydrolyzed octadecyltriethoxysilane to self-assemble from a dilute hydrocarbon solution. The alkyl chains in the monolayer deposited by this method appear to be in a pseudocrystalline environment. Contact angle measurements and Fourier transform infrared spectroscopy indicate that the layer is in all respects equal to a Langmuir-Blodgett monolayer in packing density (almost-equal-to 20 angstrom 2/molecule) and order, but the adhesion of the self-assembled monolayer to the mica surface is much better than that obtainable by any other method of monolayer formation. The self-assembling species, octadecylsilanetriol or low order oligomers, is shown to be surprisingly stable to condensation in dilute solution. The ability to form robust, well-ordered monolayers on mica should open up new possibilities for tailor-made surfaces to be studied in the surface forces apparatus.