Electrochemical and transport properties of templated gold/polypyrrole-composite microtube membranes

We have been investigating the transport properties of nanotube membranes prepared via the template method. Membranes containing gold (Au) nanotubes prepared by electroless deposition of Au within the pores of commercially available filters have been studied most extensively. The advantage of these membranes is that the inside diameter of the Au nanotubes can be precisely controlled down to molecular dimensions. Currently, we have no other materials synthesis strategy that allows for such precise control over the diameter of the nanotubes obtained. We are interested in developing such chemistries so that nanotubes having any desired inside diameter that are composed of materials other than metals can be prepared. We describe here the electrochemical polymerization of polypyrrole (PPy) microtubes within templated prepared Au microtubes. We demonstrate that the effective inside diameter of the PPy microtubes can be controlled by varying the number of voltammetric scans used during the PPy electropolymerization. The electrochemical characteristics and transport properties of these composite Au/PPy microtube membranes are described here. (C) 2003 The Electrochemical Society.