Enhancement of the thermoelectric property of nanostructured polyaniline/carbon nanotube composites by introducing pyrrole unit onto polyaniline backbone via a sustainable method

Abstract

The electrical conductivity of conducting polymer depends strongly on the alignment of the polymer chains, and a fully aligned polymer backbone strongly enhances the conjugation. Herein, the pyrrole unit was introduced onto the polyaniline backbone to improve the alignment of the polyaniline (PANi) main chain. The nanostructured poly(aniline-co-pyrrole) random copolymer (PANiPy) was successfully synthesized via a sustainable method without mechanical agitation. FTIR, Raman and XPS spectra confirmed the strong interaction between the pyrrole and the aniline units. Single wall carbon nanotubes (SWCNTs) were applied to improve the membrane forming performance of insoluble conjugated polymers and the polymer/SWCNT composites were prepared. The SEM results revealed that the synthesized polymer exhibited a nanostructured morphology. Nanostructured PANiPy was well dispersed in the SWCNT bundles and formed a self-assembled layered morphology. The PANiPy/SWCNT composite film achieved the highest power factor of 98.5 μW·m−1·k−2, which was much higher than that most carbon-based thermoelectric composites. The results demonstrated that introducing the pyrrole units onto the PANi backbone was a good strategy to tune the alignment of PANi chain, and the thermoelectric performance of PANi/SWCNT composite was enhanced. Moreover, the experimental procedure is attractive as a sustainable process for materials preparation in chemical engineering.