INVESTIGATION OF MOLECULAR AND SUPERMOLECULAR STRUCTURE IN TEMPLATE-SYNTHESIZED POLYPYRROLE TUBULES AND FIBRILS

Nanotubules and nanofibrils of polypyrrole were chemically synthesized using the pores of nanoporous polycarbonate membrane filters as templ ates, We have previously shown that such ''template-synthesized'' nano fibrils of polypyrrole can have enhanced conductivities relative to mo re conventional forms of the polymer (e.g., thin films), Furthermore, we have shown that this enhancement in conductivity is critically depe ndent on the diameter of the nanofibrils; the narrowest diameter fibri ls show the greatest enhancements in conductivity, In this paper we ex plore the genesis of this enhancement in conductivity by determining t he relative conjugation lengths in the polypyrrole fibrils using FTIR and UV-visible-NIR spectroscopies. Using polarized infrared absorption and FTIR spectroscopies, we have followed the evolution of polymer ch ain orientation and conjugation length with polymer chain growth on th e pore wall of the template membrane. On the basis of these results, w e have proposed a bilayer model to explain the enhancement in conducti vity and its strong dependence on fibril diameter.