Conducting polymer solutions

Abstract

The discovery that conducting polymers were soluble created a great deal of surprise among scientists active in that field. These solid-state, electronically conductive polyelectrolytes had never demonstrated a tendency to dissolve and had been deemed intrinsically insoluble. Among the proposed causes for insolubility are high crystallinity and backbone rigidity. The usual entropic barriers to dissolution of macromolecules are reinforced by the high degree of order imposed on these molecules as a requirement for electroactivity. Thus an explanation for the recently observed solubility of conducting polymers must stem from other properties. It now appears that the solubilization mechanism involves solvation of both reactive radical intermediates and dopant counterions. In our discussion the doping process is treated as a means of generating reactive chemical intermediates. The techniques used to produce conducting polymer solutions and analytical data derived from them are presented and interpreted in terms of aiding in the definition of the chemical species responsible for conductivity in this class of organic materials. Finally, an extension of the use of these solutions into the synthesis of conducting polymers is presented.Polymers with conjugated a-electron backbones display unusual electronic properties compared to conventional po1ymers.l These properties include (1) low-energy optical transitions, (2) low ionization potentials, and (3) high electron affinities. The result is a class of polymers which can be oxidized or reduced more easily and more reversibly than conventional polymers. Charge-transfer reagents ("dopants") effect this oxidation or reduction2 and in doing so convert an insulating polymer to a conducting polymer with near metallic conductivity in many cases. The unique feature of conducting polymers is that they combine the properties of two widely divergent classes of materials: plastics and metals. The potential result is a material with the chemical and mechanical attributes of polymers and the electronic properties of metals or semiconductors.

Spectroscopic and Theoretical Determination of the Electronic Structure of Anisole, Thioanisole, and Methoxy- and Methylthiobenzonitriles: A Contribution to the Study of Organic Conducting Polymers

“…The smaller π s -IE and π s *-AE values of the sulfur derivatives PhSMe and p-NCPhSMe with respect to the corresponding methoxy derivatives suggest that PPS has a smaller HOMO-LUMO energy gap than PPO and a better possibility to give rise to materials with high electric conductivity when properly doped as, in fact, observed for low doping levels. 26,27 The electron relaxation energy (E relax ) accompanying positive ionization can be taken as an independent estimate of polarizability. It can be noticed (see Table 1) that the first experimental IE value for the φ ) 0°rotamer of PhXMe and p-NCPhXMe is reproduced within 0.12 eV by the HF/6-31G** calculations at the Koopmans' theorem level.…”

“…21,26 PPO and its precursors, however, have been much less investigated. 27 The doping process under mild conditions has been reported to give rise to polymers with much smaller σ values than PPS doped under the same conditions, 26,27 that is, where irreversible chemical reactions (involving C-C bond formation) do not occur. The different behavior of oxygencontaining polymers with respect to the corresponding sulfur derivatives is not yet well understood.…”

A hybrid material of graphene and poly (3,4-ethyldioxythiophene) with high conductivity, flexibility, and transparency

“…Organic conducting polymers have received increasing attention as possible transparent and conductive materials because of their efficacious optical [4] and electronic [5] properties, and potential applications in fl exible electronic devices [6,7]. Poly (3,4-ethyldioxythiophene) (PEDOT) represents one such conjugated polymer that can be used as the active material in flexible organic electronics due to its remarkably high conductivity, transparency, and environmental stability [8], but its insolubility appears to be a major drawback in terms of processing for incorporation in devices.…”

Fabrication and Characterization of Hybrid Photovoltaic Devices Based On N-Type GaAs and Polymer Composites

“…For the organic part, conducting polymers are used, because of their optical and electrical properties and possible flexibility [9][10][11][12]. The conjugated polymer blend, PEDOT:PSS, is a good example of such an organic material [3].…”