Polymeric photoacid generators for direct photochemical modification of surface

Abstract

To achieve easy spin coating and enhanced efficiency in the photolithographic process for the direct photochemical modification of surface, we incorporated photoacid generator WAG) into polymer backbone. Bis-(4-hydroxy-phenyl)-(4-methoxy-3,5-dimethyl-phenyl)-sulfonium chloride was synthesized as a monomer, and was polymerized with sebacoyl chloride and terephthaloyl chloride. The resulting polymeric PAG in chloride salt form was converted to the p-toluenesulfonate and 1-naphthol-5-sulfonate forms with ion-exchange reactions. By the photolithographic process with the polymeric PAG, the protecting groups of the linker molecules self-assembled onto a glass plate were micropatterned to produce an amine pattern for the microarray of oligonucleotides. The acids generated from the polymeric PAG effectively deprotect the acid-labile protecting groups of the linker molecules through a chemical amplification process in the exposed region. After the treatment of the patterned amino groups with a fluorescent dye, the pattern profiles were observed with a fluorescence scanner. The fluorescence image reveals a well-defined pattern at a micro level, which clearly indicates that the polymeric PAGs have a great potential in photochemical surface modification for the microarray of oligonucleotides. Copyright (c) 2007 John Wiley & Sons, Ltd.