文摘
We describe a simple experimental approach for delivering self-assembled monolayers (SAMs) ofoctadecylphosphonic acid (OPA) on many oxide surfaces using a nonpolar medium with a dielectric constantaround 4 (e.g., trichloroethylene). This approach readily results in the formation of full-coverage OPA SAMson a wide variety of oxide surfaces including cleaved mica, Si wafer, quartz, and aluminum. Especially, theavailability of delivering full-coverage OPA SAM on a Si wafer is unique, as no OPA SAMs at all could beformed on a Si wafer when using a polar OPA solution. The reason a nonpolar solvent is superior lies in thevery fact that the hydrophilic OPA headgroup tends to escape from the nonpolar solution and is thus enrichedat the medium-air interface. It is these OPA headgroups seeking a hydrophilic surface that make possible thewell-controlled OPA monolayer on an oxide surface.