New photolabile functional polymers for patterning onto gold obtained by click chemistry

Nitroxide-mediated radical polymerization (NMRP) was used for the synthesis of the random copolymer poly[styrene-r-(4-propargyloxystyrene)] with a narrow molecular weight distribution (PDI similar to 1.2). The material was postfunctionalized by polymer analogous reactions and via Cu(I)-catalyzed 1,3-dipolar cycloadditions ("click chemistry approach") to provide a family of photopatternable functional polymers for nanotechnology applications. For this, a series of azides were designed in order to incorporate subunits with specific properties into the materials. Photopatterning was made possible by the introduction of units with a photoremovable amino protecting group (PRG) (nitroveratryloxycarbonyl, NVOC) which may lead to the release of amino functions after selective UV/laser irradiation. Covalent attachment of the functional polymers onto gold was promoted by sulfide-containing anchoring units again introduced as pending groups onto the polymer backbone via the 1,3-dipolar cycloaddition reaction. The modified materials were obtained in almost quantitative yields under mild conditions according to IR and NMR studies. Thermal characterization was accomplished by DSC and TGA. Click chemistry is once more proven to be a useful tool for material science, in this particular case for the preparation of functional polymers for photopatterning with modulated properties.