Processing parameters to enhance the electrical conductivity and thermoelectric power factor of polypyrrole/multi-walled carbon nanotubes nanocomposites

Charge transport properties of intrinsically conducting polymers (ICPs) is highly related to their microstructures. Processing conditions and material formulations can alter the morphology of ICPs and thereby their electrical and thermoelectric (TE) properties. In this paper, the effects of different processing and material parameters on the electrical conductivity and TE performance of polypyrrole (PPy)/multi-walled carbon nanotubes (MWCNTs) nanocomposites were investigated. PPy/MWCNT nanocomposite samples were prepared by in-situ oxidative polymerization method. The effects of polymerization time, oxidant-to-monomer ratio, filler-to-monomer ratio, and reaction medium on electrical conductivity and Seebeck coefficient of the fabricated PPy/MWCNT nanocomposites were investigated to optimize the TE efficiency of PPy/MWCNT nanocomposites. The results revealed that, the MWCNT-to-monomer molar ratios of 0.1 and 1 provided the highest electrical conductivity and the maximum power factor, respectively. Addition of methanol to the reaction solution system led to finer structures in the nanocomposites and enhanced their electrical conductivity as well as their TE efficiencies.