Synthesis and Characterization of Polyvinylferrocene/Polypyrrole Composites

Conducting polymer composites of polyvinylferrocene and polypyrrole (PVF/PPy) were synthesized chemically by the in situ polymerization of pyrrole in the presence of PVF using FeCl₃ as oxidant. Acetic (CH₃COOH) and boric (H₃BO₃) acids were used as the synthesis medium. Effects of the synthesis medium on the properties of the PVF/PPy composite were investigated. The PVF/PPy composites and homopolymers were characterized by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and magnetic susceptibility techniques. Conductivity measurements were performed using the four‐probe technique. We found that the conductivities of PVF/PPy‐H₃BO₃ (1.19 S cm⁻¹) and PVF/PPy‐CH₃COOH (4.5×10⁻¹ S cm⁻¹) increased relative to those of the homopolymers of PPy‐H₃BO₃ (2.1×10⁻² S cm⁻¹) and PPy‐CH₃COOH (1.2×10⁻² S cm⁻¹) due to the interaction of PVF with the pyrrole moiety. The stability of all homopolymers and composites were investigated by thermogravimetric analysis and by conductivity measurements during heating‐cooling cycles. There was a small drop in conductivity caused by the annealing of PVF/PPy composites at 70°C. The conductivity of all samples increased with temperature and exhibited stable electrical behavior with increasing temperature. TGA analysis of samples showed that the composites were more stable than the homopolymers or PVF separately. The magnetic susceptibility values of samples were negative, except for PVF/PPy‐H₃BO₃. Morphology changes of the composites investigated by scanning electron microscopy (SEM), attributed to synthesis conditions, have a significant effect on their conductivity.

Keywords:

• polyvinylferrocene
• polypyrrole
• composite
• conductivity
• thermal stability

5 Acknowledgments

The authors would like to thank the Scientific and Techological Research Council of Turkey for the financial support to perform the present study (project number TBAG‐HD/42 (105T055) and Suleyman Demirel University Research Foundation (project number 1003‐d‐05).