Multistep filling of porous silicon with conductive polymer by electropolymerization

Abstract

The filling of porous silicon with polypyrrole by electropolymerization was investigated. The filling with polypyrrole proceeded preferentially along the porous silicon wall, leading to the formation of tubular structures. By repeating the porosification, the pore filling and the additional porosification, through-tubes of polypyrrole were formed in macropores. The technique to form through-tube was also applied to medium-sized pores. A double layer with polypyrrole was produced by the repetition of porosification and pore filling twice. The immobilization of glucose oxidase was performed by electropolymerization in an aqueous solution containing glucose oxidase and pyrrole. Glucose oxidase was immobilized physically in the polypyrrole film. In the double layer, the sensitivity of glucose oxidase was measured by electrochemical oxidation of hydrogen peroxide, which was produced by the enzymatic reaction of glucose oxidase to gluconolactone. When glucose oxidase was immobilized in the upper layer, glucose was detected sensitively. On the other hand, when glucose oxidase was immobilized in the lower layer, the sensing current showed a slow and a low response. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)