Electrosynthesis and optical characterization of poly(p-phenylene), polypyrrole and poly(p-phenylene)-polypyrrole films

Abstract

Poly(p-phenylene) (PPP), polypyrrole (PPY), and poly(p-phenylene-pyrrole) (PPP-PPY) films were electrochemically synthesized in acetronitrile by cyclic voltammetry. For comparison purposes, the films were characterized by cyclic voltammetry in a monomer-free solution, and their optical responses were also obtained in the UV-VIS range of energy after varying the applied potentials. The absorbance spectra of the PPP-PPY film exhibited bands typically seen in the spectra of the homopolymers, PPP and PPY films, but better defined, intense, and related to reversible color transitions. Although it was not possible to confirm by using infrared and Raman spectroscopy that a copolymer was in fact obtained, the presence of both monomers, pyrrole and biphenyl, in the polymerization medium turned easier the process of film formation, yielding darker, more uniform, and rougher films as it was verified by photographic images and AFM (atomic force microscopy) images.

Electrosynthesis of poly(p-phenylene) and poly(p-phenylene/pyrrole) films under controlled humidity

“…5) exhibits spectral profiles close to those reported for PPY at different applied potentials (Soares et al, 2014). On the other hand, the spectra for the PPP-PPY film/Route II show an absorption region at higher wavelengths, which increases in intensity at a higher number of cycles, thereby characterising a combination of profiles from PPP and PPY.…”

“…However, after doping, two other bands can be seen due to the transition from the valence band to polaron-bipolaron states of PPP. In this case, it may be assumed that the presence of water in the polymerisation medium causes an effect similar to that observed for films to which different potentials were applied (Soares et al, 2014).…”

“…The literature reports similar absorption bands in the spectra of PPP films after applying different potentials, i.e. at different doping levels (Soares et al, 2014;Lee et al, 2001). The PPP spectrum typically shows a sinBrought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 9/30/15 11:46 AM Table 1.…”

“…In this case, the electrosynthesis protocols are key steps in the preparation of stable and uniform polymer films, in particular composites. In a previous study, PPP films were prepared with a common solvent (acetronitrile) and a common electrolyte (tetrabutylammonium perchlorate) by electro-oxidising biphenyl in the presence or *Corresponding author, e-mail: gdebora@ifsc.usp.br Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 9/30/15 11:46 AM absence of pyrrole at a 10 : 1 mole ratio (Soares et al, 2014). However, after repeating the experiments, the film surface quality was observed to vary depending on whether the measurement was conducted on wet or dry days.…”

A Long π-Conjugated Poly-para-Phenylene-Based Polymeric Segment of Single-Walled Carbon Nanotubes

“…3 PPP is an insulator in neutral form, but its conductivity can increase to >100 Scm -1 after chemical doping. [8][9] From the point of view of chemical synthesis, PPP contains only sp 2 -carbon atoms and can be considered as conjugated segments of many carbon allotropes such as graphene, graphene nanoribbons, and carbon nanotubes (CNTs). Recently, Basagni and coworkers used a stepwise on-surface polymerization reaction to synthesize oriented graphene nanoribbons via the key intermediate of a PPP polymer.…”