Photochemical attachment of polymer films to solid surfaces via monolayersof benzophenone derivatives

We report a simple and yet effective way to photochemically attach thin pol ymeric layers to solid surfaces. The system is based on a photoreactive ben zophenone derivative that is bound to SiO2 surfaces via a silane anchor. Th is substrate is then covered with a polymer film that is reacted with the b enzophenone moieties by illumination with UV light (lambda > 340 nm). As a result of the photochemical reaction, a thin layer of the polymer is covale ntly bound to the surface. Nonattached polymer is removed by extraction. As examples, we have successfully attached thin layers of poly(styrene) and p oly(ethyloxazoline). The thickness of the layer is a function of the illumi nation time and the molecular weight of the polymer. The film thickness inc reases linearly with the radius of gyration of the polymers used for attach ment. Using this system, we were able to photochemically attach up to 16 nm thick films of poly(styrene).