Photochemical attachment of polymers on planar surfaces with a covalently anchored monolayer of a novel naphthyl ketone photochemical radical generator

Abstract

A monolayer of covalently anchored, novel, binaphthyl ketone is used as a surface-confined photochemical radical generator (PRG) for anchoring a variety of polymers to silicon surfaces. The precursor PRG is synthesized by the application of a facile and novel method for the oxidation of sterically hindered benzylic hydrocarbons to carbonyl compounds. Oxidation was carried out with a stoichiometric amount of potassium peroxydisulfate, in the presence of a catalytic amount of copper sulfate in an acetonitrile/water mixture. The PRG synthesized is characterized by 1 H NMR, UV, and Fourier transform infrared (FTIR). The covalently attached monolayers are characterized by X-ray photoelectron spectroscopy, ellipsometry, and water contact angle measurements. The method developed is applicable to the preparation of a monolayer of a variety of polymers on a wide range of substrates carrying surface hydroxyl groups.

Surface Chemoselective Phototransformation of C–H Bonds on Organic Polymeric Materials and Related High-Tech Applications

“…It generally shows a lower reactivity than BP in hydrogen abstraction reactions . By use of a silane carrying a binaphthyl ketone moiety (Chart ), binaphthyl ketone can be immobilized on a target substrate, which is subsequently used as a surface-confined photochemical radical generator (PRG) to capture a variety of polymers onto silicon surfaces, and micropatterned immobilization of polymers is thus obtained (Figure ) …”

“…A silane molecule carrying a binaphthyl ketone moiety and the grafting of a patterned polymer film on binaphthyl ketone-terminated silane SAMs as revealed by the subsequent fluorescence labeling seen under a fluorescence microscope. Reprinted with permission from ref . Copyright 2004 WILEY-VCH Verlag GmbH & Co. KGaA.…”

Shedding light on surfaces—using photons to transform and pattern material surfaces

“…Phthalimides, 26 benzophenone 81 and binaphthyl ketone 82 have been used to prepare surfaces that photograft a wide variety of pre-existing polymers via photo-addition reactions. Photografting reactions have been used to covalently immobilize numerous polymers in a host of applications including carbohydrate microarrays, 83 protein patterning, 84 lipid bilayers, 85 and coatings for biomedical devices.…”

Electroless Deposition of Nickel on Photografted Polymeric Microscale Patterns

“…A number of photoactive interfaces based on photogenerated ketyl radicals, nitrenes, and carbenes have been shown to covalently bind polymers to the surface of a variety of substrates including glass, silicon, gold, titanium, aluminum, and polymers . Among aromatic ketones, benzophenone, phthalimide, and binaphthyl ketone have been used to construct surfaces that covalently bind a wide variety of preexisting polymers. Similarly, carbenes and nitrenes have been photogenerated on surfaces derivatized with azidobenzoyl, aryl trifluoromethyl and ethyl diazirine, azidoformate, aryl sulfonyl azide, and diazomethylcarbonyl .…”