Carbon nanotube-polyaniline nanohybrids: Influence of the carbon nanotube characteristics on the morphological, spectroscopic, electrical and thermoelectric properties

We report on the fabrication of polyaniline (PANI)/carbon nanotube (CNT) nanohybrids using a novel approach of CNT-templated polymerization process. The physical properties of the nanohybrids can be tuned by keeping a constant amount of CNTs and changing their nature, i.e., using single-walled, multiple-walled, oxidized or unoxidized. SEM investigations evidenced fibrous morphology in all PANI/CNT hybrids with nanometer-sized diameters. Spectroscopic (UV–vis, IR and Raman) analyses of the nanocomposites evidenced good π–π interactions between PANI rings and CNTs. X-ray crystallography supports the presence of nanocrystalline domains at 2θ ∼6.5°. Electrical and thermoelectric properties of nanohybrids containing: (a) unoxidized MWNTs or (b) oxidized SWNTs or oxidized MWNTs are reported for the first time. In the series of samples studied, the PANI/unoxidized SWNTs provided the most promising electrical (conductivity: σ = 530 S cm−1) and thermoelectric characteristics (seebeck coefficient: S = 33 μV K−1 and power factor: PF = 0.6 μW m−1 K−2).