Further study of the preparation and properties of poly(thienylene vinylene) via an organic-soluble precursor polymer

Abstract

Effects of reaction conditions on the preparation of a precursor polymer of poly(thienylene vinylene) (PTV) which is soluble in organic solvents and on the electrical and mechanical properties of the PTV produced have been studied. The results show that among the bases used in polymerization, LiOH and NaOH were more favourable than other alkalis. The optimum monomer concentration was 0.1–0.3 M. Polymerization in a mixture of water and methanol with 1:1 to 1:3 V/V produced a precursor polymer which was soluble in organic solvents. Polymerization temperature is preferably at −10 to −20 °C in order to get a high polymer yield and good solubility of the precursor polymer. Polymerization proceeded very rapidly during the first hour and then became slow. Addition of petroleum ether could improve the polymer yield to some extent. The elimination reaction of the precursor polymer to form PTV took place at about 195 °C. Above 400 °C, the PTV was unstable and oxidative decomposition took place. Conductivity, after I 2-doping, of PTV produced in this way reached about 65 Scm −1, and had an excellent air-stability, even after six months storage in air. The PTV film also possessed good mechanical properties, with a tensile strength above 50 MPa. It also exhibits a strong absorption at 550 nm.