Synthesis And Thermoelectric Properties Of Copolymers Of Aniline And Ortho-substitute Aniline

Conducting polymers had attracted tremendous attention because of its unique electrical and optical properties coupled with numerous potential applications such as energy storage, electromagnetic interference shield, molecular recognition and optoelectronic devices. Amongst the conducting polymers, polyaniline (PAn) and its derivatives were unique because of their good environmental stability and controllable electrical properties.In this paper, we had reported the synthesis of poly (aniline-co-o-toluidine) and poly (aniline-co-o-anisidine) by chemical peroxidation method. The structures of copolymers had been characterized by IR, 1HNMR and elemental analysis and the thermal stability had been tested by TG. Electrical conductivity, Seebeck coefficient and Thermal conductivity were measured, and the ZT were calculated. The transport parameters for thermoelectric properties of copolymers were determined and compared to polyaniline. Calculated the electron-donating group content in the copolymer chains and discussed the group content dependence of thermoelectric properties of the copolymers. The result showed that:1. The copolymers yield decreased with increasing of oxidation when other conditions were same and increasing of the acid concentration when other conditions were same. The electron-donating group content in the copolymer chains increased with increasing of the ortho-substitute aniline content in the feed ratio of the monomers, and decreased with the increasing of the oxidant.2. The thermal stability of copolymers was better than PAn' and the poly (aniline-co-o-toluidine)'s better than poly (aniline-co-o-anisidine) in the same condition.3. Electron-donating group content and the doping level were the influencing factor of electrical conductivity, Seebeck coefficient and thermal conductivity of copolymers.4. For high doping level, the electrical conductivity of poly (aniline-co-o-toluidine) increased with the increasing of temperature; for low dopinglevel, the electrical conductivity increased and then decreased with the increasing of temperature. However, the Seebeck coefficient increased with the increasing of temperature all along.5. The electrical conductivity of poly (aniline-co-o-anisidine) increased and then decreased with the increasing of temperature, and got the peak value at 303K. The Seebeck coefficients had the same tendency to poly (aniline-co-o-toluidine).6. The copolymers had lower thermal conductivity, about 0.005W·cm-1·K-1, so the structure modified had a little effect on it.7. The electron-donating group content was not the only influencing factor to the ZT of copolymers. The ZT increased with the electron-donating group content in the same acid concentration, and higher than PAn at the same condition. In these samples, for poly (aniline-co-o-toluidine), it got the maximum ZT was 1.508×l0-4; for poly (aniline-co-o-anisidine), the maximum ZT was 2.125×10-5.But for the poly (aniline-co-o-anisidine), the ZT had a sharp decrease when the anisyl content was very high.