Synthesis and gas sensing properties of poly [tetra( pyrrol-l-yl)silane]

Conducting polymers such as polypyrrole and polythiophene offer a new approach to the design of modified electrodes and sensors. In the current work, the electrochemical and chemical polymerisation of tetra(pyrrol-1-y1)silane is described. Resultant polymers with different anions have been characterised by electrochemical methods, XPS and microanalysis. Molecular geometry calculations suggest that both inter- and intra-molecular couplings are present in the film. Crosslinking of the polymeric matrix via b-linkages will result in a three-dimensional structure with a concomitant reduction in the degree of conjugation, accounting for the low film conductivity (sigma ca. 10-6 S cm-1). Preliminary results show that poly [tetra(pyrrol-1-yl)silane] is a promising material for the fabrication of gas sensors. It is unexpectedly sensitive to ammonia and trimethylamine gas when compared with polypyrrole and poly(N-methylpyrrole) prepared in a similar fashion.