Templated growth of polyaniline on exfoliated graphene nanoplatelets (GNP) and its thermoelectric properties

Polyaniline (PANi)/exfoliated graphene nanoplatelets (GNP) nanocomposites were prepared by in situ polymerization of aniline monomer in the presence of GNP for thermoelectric applications. PANi has a strong affinity for GNP due to π electron interactions, forming a uniform nanofibril coating. A paper-like nanocomposite was prepared by controlled vacuum filtration of an aqueous dispersion of PANi decorated GNP. The Seebeck coefficient of the resulting nanocomposite changes with initial concentration of aniline in the solution as well as the protonation of PANi, reaching as high as 33 μV/K for nanocomposites containing approximately 40 wt% of PANi and with a protonation ratio of 0.2. The presence of GNP improved the electrical conductivity of the nanocomposites to 59 S/cm. As a result, thermoelectric figure of merit ZT of the nanocomposites is 2 orders of magnitude higher than either of the constituents, exhibiting a significant synergistic effect.