Electrochemistry of Conductive Polymers: XXV. Electrochemical Preparation and Characterization of Poly(p-phenylenes) from Biphenyl and p-Terphenyl

Poly(p-phenylene) (PPP) films were prepared by anodic oxidation of biphenyl and p-terphenyl in a rigorously dried dichloromethane solution with 0.10 M tetrabutylanimonium tetrafluoroborate as an electrolyte. The polymer growth and film properties were studied using cyclic voltammetry, electrochemical quartz crystal microbalance, infrared spectroscopy, and in situ spectroelectrochemical techniques. The results indicate that p-terphenyl is polymerized more efficiently than biphenyl and the PPP film prepared from p-terphenyl shows more reversible doping and dedoping properties than that from biphenyl. Electrochemical quartz crystal microbalance studies show that the faradaic efficiencies are much higher for polymerization of p-terphenyl compared to that for biphenyl. The infrared spectroscopic measurements for an estimation of chain lengths reveal that PPP is composed of an average of about 7.4 and 8.4 phenyl rings when synthesized from biphenyl and p-terphenyl oxidation, respectively.