Electrochemical Properties of a Self-Dopable Ionic Conjugated Polymer: Poly[2-ethynyl-N-(4-sulfobutyl)pyridinium betaine]

The electrochemical properties of a self-dopable conjugated polymer, poly[2-ethynyl-N-(4-sulfobutyl)pyridinium betaine] (PESPB) were studied. PESPB was prepared by the polymerization of 2-ethynylpyridine with the ring-opening of 1,4-butanesultone in high yield. The cyclovoltamograms of this polymer exhibited reversible electrochemical behaviors between the doping and undoping peaks. The kinetics of the redox process of this polymer was found that it is almost controlled by the diffusion process from the experiment of the oxidation current density of polymer versus the scan rate. The photoluminescence (PL) spectra of polymer showed that the photoluminescence peak is located at 511 nm, corresponding to a photon energy of 2.43 eV.