Polythiophene derivatives self-doping

Water-soluble derivatives of polythiophene have been made allowing counterions bound to the polymer backbone to self-dope with the protons (e.g., lithium and sodium ions) injecting electrons into the pi-system. Thus, combinations of sodium salts and proton salts (e.g., prepared from poly-3-(2-ethanesulfonate)thiophene) have been prepared that are both water-soluble and conducting. 

Figure 1.13 Oxidation-reduction reactions of polythiophene derivatives showing self-doping during the oxidation reactions. (Reprinted from Synthetic Metals, 20, A. O. Patil, Y. Ikenoue, N. Basescu, N. Colaneri, F. Wudl, A. J. Heeger, 151. Copyright (1987), with permission from Elsevier.)...

Figure 1.20 Various self-doped polythiophene derivatives.

Shortly after discovery of methods for preparation of organic soluble derivatives of poly(phenylene vinylene) and polythiophene, Wudl and coworkers reported preparation of each of these polymers with sulfonated side groups. The specific objective of this work was based on the idea that the anionic sulfonate groups could make the polymers self-doping , wherein the covalently linked anionic units could serve to provide charge compensation when the polymer backbone is in the oxidized (semiconducting) state. These first studies focused on the synthetic monomer and polymer chemistry. However, the authors reported in their papers that their newly synthesized conjugated... 

Self-doped polythiophenes. . 834 3.1 Sulfonic acid derivatives. . . 845... 

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