Preparation, characterisation and biosensor application of conducting polymers based on ferrocene substituted thiophene and terthiophene

Novel ferrocene-substituted thiophene and terthiophene compounds, trans-1-(3-thienyl)-2-(ferrocenyl)ethene and trans-1((2',2":5",2"'-terthiophen)-3"-yl)-2-(ferrocenyl)ethene, have been used to produce homopolymer and copolymer materials. The copolymer of trans -1-(3'-thienyl)-2-(ferrocenyl)ethene with pyrrole and the homopolymer of trans-1-((2',2":5",2"'-terthioplien)-3"-yl)-2-(ferrocenyl)ethene were characterised using cyclic voltammetry (CV), UV-visible spectroscopy, scanning electron microscopy (SEM) and four point probe conductivity measurements. Results obtained suggest that the ferrocene moiety plays a catalytic role in the electropolymerisation process. Both the copolymer and homopolymer displayed cyclic voltammograms with redox peaks that can be assigned to the ferrocene moiety and the polymer backbone. The UV-visible spectra and morphology of the copolymer of trans-1-(3'-thienyl)-2-(ferrocenyl)ethene with pyrrole were similar to those of polypyrrole, but the spectra and morphology of the homopolymer of trans-1-((2',2":5",2"'-terthiophen)-3"-yl)-2-(ferrocenyl)ethene were different from those of polyterthiophene. The conductivity of the copolymer was determined to be 0.13 S cm(-1) whereas that of the homopolymer of trans-1-((2,2":5",2"'terthiophen)-3"-yl)-2-(ferrocenyl)ethene was 82.6 muS cm(-1). The copolymer or homopolymer modified Pt disk electrodes facilitated access to the redox centre within Cytochrome C during CV, and their potential use as biosensors has been demonstrated. (C) 2002 Published by Elsevier Science Ltd.