Design Strategies for the Preparation of Polymeric Organic Superconductors

摘要

Several copolymers were synthesized in which the known superconducting precursorbis-ethylenedithiot etrathiafulvalene, BEDT-TTF ('ET'), was incorporated as a formal repeat unit into aliphatic and aromatic polyesters as well as an aliphatic polyurethane. These polymers could be cast as optically quality thin films. All polymers could be oxidized to either monocation or dication forms in solution with antimony pentachloride, in which all the ET subunits had been oxidized. Et subunits could also be attached as pendant groups on a poly (methyl methacrylate) backbone with up to 60% incorporation. All of the polymers were thermally stable to above 200 degrees C. , and were fully characterized by both DSC, TGA and GPC. Cyclic voltammetry clearly showed that the incorporated ET subunits were electroactive, with two redox peaks showing the successive formation of the radical cation and dication peaks. Room temperature DC conductivities for the polymer films before and after oxidative doping were obtained, with conductivities of the oxidized films generally falling between 10(exp -6) to 10(exp -4) S/cm. Several attempts to incorporate TTF subunits into copolymer formulations proved to generally unsuccessful, although this research is continuing.