New poly(p-substituted-N-phenylpyrrole)s. Electrosynthesis, electrochemical properties and characterization

• Published in: Synthetic metals Vol. 179; pp. 74 - 85
• Main Authors: Diaw, A.K.D., Gningue-Sall, D., Yassar, A., Aaron, J.J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-09-2013; Elsevier
• Subjects: Applied sciences; Electrochemical properties; Electropolymerization; Exact sciences and technology; Physicochemistry of polymers; Poly(p-substituted-N-phenylpyrrole)s; Polymerization; Polymers and radiations; Spectroscopic characterization; Poly(p-substituted-N-phenylpyrrole)s; Electrochemical properties; Spectroscopic characterization; Electropolymerization; Substituent effect; Molecular structure; Aromatic polymer; Pyrrole derivative polymer; Experimental study; Electrochemical polymerization; Functional polymer; Conducting polymers; Thiophene derivative polymer; Morphology; Preparation
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/j.synthmet.2013.07.016

•Electrosynthesis of poly(p-substituted N-PhPyr)s electroactive films on Pt.•Electrochemical properties of polymer films depend on the substituent nature.•Couplings in the pyrrole ring 2,5 positions.•Film doping levels vary with the substituent electron-donor character.
Poly(N-p-hydroxyphenylpyrrole) [poly(HOPhPy)], poly(N-p-methoxyphenylpyrrole) [poly(MeOPhPy)], poly(N-p-thiophene-phenylpyrrole) [poly(ThPhPy)], poly(1,1′-phenylene dipyrridyl) [poly(PhDPy)] and poly(1,1′-diphenylene dipyrridyl) [poly(DPhDPy)] were electrosynthesized from the corresponding monomers on Pt electrode in 0.1M tetrabutylammonium hexafluorophosphate (TBAPF6) acetonitrile solutions, using cyclic voltammetry (CV), galvanostatic and potentiostatic modes. The electrodeposited films were characterized by CV, FT-IR spectrometry, X-ray photoelectron spectra (XPS), and scanning electron microscopy (SEM). Electron-donating substituent effects on the polymer electrochemical properties were investigated by CV. The CV of the films indicated a good redox behaviour and a peak position depending on the nature of substituent. FT-IR spectral studies allowed one to predict a linear and regular structure of the polymer chains, the coupling taking place in the 2 and 5 positions of the pyrrole rings. XPS analysis showed a variation of the film doping levels (26–42% for oxidized films and 6–12% for reduced films) with the electron-donor character of the phenyl p-substituents. The conjugated π-electronic system was extended by strong electron-donating substituents which led to a higher doping level of the polypyrrolic chains and a polymer structure with high-energy and polar bonds like CN+ and CN+. SEM analysis revealed changes in the polymer film morphology and thickness with the nature of substituents.