UV induced attachment of ultrathin polymer films on silicon wafers

We report two approaches to the attachment of ultrathin polymer films on silicon wafers. In the first method, a photoactive crosslinking agent was used to covalently immobilize a "monolayer" of polymer on silicon wafers. The thickness of the film was controlled by the type and the molecular weight of the polymer. The method is versatile due to the general C-H and/or N-H insertion reactions of crosslinker; and therefore, no specific reactive functional groups on the polymers are required. The second method achieved the attachment of polymer thin films on silicon wafers via UV irradiation. The procedure consisted of spin-coating a polymer film onto a silicon wafer and irradiating the film with UV light. Following solvent extraction, a thin film remained. The thickness of the film, from a few to over a hundred nanometers, was controlled by varying solution concentration and the molecular weight of the polymer. The photochemical nature of these methods allowed the patterning of polymer thin films and arrays. These arrays displayed not only spatial features, but also unique surface topographies.