School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, P.R.China

Speech Title: Thermoelectric Polypyrrole/Carbon Nanoparticle Composites
Abstract: Organic thermoelectric (TE) materials have aroused great interest in academia due to their advantages over inorganic materials. Among various conducting polymers, polypyrrole (PPy) is widely applied in the fields of microelectronics, electrochemistry and biological technology because of its good environmental stability, low toxicity and adjustable electrical conductivity. However, the relatively low TE property plus difficult dissolution and dispersion characteristics of PPy endow PPy and its composites with TE performance far below the level for industrial application. Therefore, it is necessary to conduct thorough research on PPy composite films for excellent TE performance in order to solve this issue facing the preparation of such films. Taking advantage of high electrical conductivity of single-walled carbon nanotube (SWCNT) and facile chemical oxidative polymerization method, the PPy/SWCNT composite TE films have been developed recently in our group. These findings are of great significance for developing novel polymer TE materials and their applications. Large-area, super flexible (minimum bending radius < 0.6 mm), stretchable and mechanically stable TE films of PPy/SWCNT cable-like nanostructure composites were prepared using in situ polymerization and vacuum filtration method, with the aid of reaction medium-ethanol to regulate the enwrapped structure of PPy on the surface of SWCNT. More importantly, after mechanical bending or stretching, no obvious deterioration of TE performance was found. Additionally, PPy nanowire was synthesized by chemical polymerization method considering their outstanding features of one-dimensional (1D) nanostructure of conducting polymers, and then a unique layered morphology of PPy nanowire/SWCNT composite film was fabricated via convenient physical mixing followed by vacuum filtration. The as-fabricated composites afforded greatly enhanced TE performance with the maximum power factor of 21.7 ± 0.8 μW m-1 K-2.
Keywords: polypyrrole; single-walled carbon nanotube; nanocomposite; thermoelectric property