Multi-functional polypyrrole nanofibers via a functional dopant-introduced process

This paper reports a functional dopant-introduced route to synthesize polypyrrole (PPy) nanofibers (60-100 nm in average diameter) in the presence of p-hydroxyl-azobenzene sulfonic acid (p-OH-ABSA) as a functional dopant. The nanofibers show a high conductivity (120-130 S/cm) and photoisomerization, which resulted from proton doping and photoisomerization of azobenzene moiety, respectively. Static and dynamic light scattering as well as freeze-fracture replication transmission electron microscope measurements (FFRTEM) showed that the self-assembled cylindrical micelles act as "soft-templates" during the formation of the nanofibers. Influence of polymerization conditions, such as the type of oxidant, the rate of oxidant addition, the concentration of reactants and polymerization time, on the fibrous morphology of PPy-(p-OH-ABSA) has been investigated. The characterizations of molecular structure, photoisomerization and electrical properties have been carried out. The method described in this study provides a simple and inexpensive route to prepare multi-functional nano-structured conducting polymers. (C) 2005 Elsevier B.V. All rights reserved.