A Study On The Thermoelectric Properties Of Graphite Oxide/Polymer Composites

Polymers have unique features of richness in resources, easy processinginto a flexible form, low density and difficulty to be corroded. Especially,polymers possess a low intrinsic thermal conductivity compared withinorganic materials, which opens up a space for their application in the field ofthermoelectric materials. Based on the public literature, this paper reviewedthe research progress on the polymers and their corresponding composites inthe field of thermoelectric materials.In this paper, insulated nylon6, conductive polyaniline and polypyrrolewere selected as matrix respectively and graphite oxide as filler, resulting ingraphite oxide/nylon6, graphite oxide/polyaniline and graphiteoxide/polypyrrole composites. At the same time, graphite oxide was reducedthermally to be graphite nanoplate, which was also selected as filler to resultin graphite nanoplate/polyaniline composites. The thermoelectric properties ofcomposites mentioned above and the effect of reduction on the graphiteoxide/polyaniline composites were studied.This paper confirmed that: nylon6was transformed from an insulatorinto a semiconductor due to that graphite oxide underwent reduction to be conductive filler in nylon6. The thermoelectric properties of nylon6wereenhanced greatly with the maximum thermoelectric figure of merit of9.45×10^-6; graphite oxide played a role of template due to its stronginteractions with monomer to foster alignment and ordered accumulation ofpolymer chains in polymerization. The increased carrier mobility resulted inboth a higher electrical conductivity and Seebeck coefficient of graphiteoxide/polyaniline and graphite oxide/polypyrrole composites than individualmatrix. The maximum thermoelectric figure of merit was4.86×10^-4and7.66×10^-4with same thermal conductivity to individual matrix, respectively;the thermoelectric properties of graphite oxide/polyaniline decreased afterreduction, which was caused by the decrease in the doping and oxidationlevels of polyaniline; the thermoelectric properties of polyaniline wereimproved by graphite nanoplate not as largely as graphite oxide.This paper verified that graphite oxide as a two-dimensional functionalmaterial, not only can optimize the thermoelectric properties of the polymer asmatrix due to its template effect, but also can be changed into conductive fillerto modify the thermoelectric properties of matrix.