Synthesis and characterization of poly(o-toluidine)/functionalized multi-walled carbon nanotubes nanocomposites with improved electrical conductivity

Poly(o-toluidine)/carboxylic acid groups contained multi-walled carbon nanotube (POT/c-MWCNT) nanocomposites has been successfully synthesized by in situ chemical oxidation polymerization using ammonium persulfate as an oxidant and sodium dodecyl sulfate as a surfactant in the absence of any added acid. The interaction between POT and c-MWCNTs and nature of chain growth have been investigated and explained according to the results of FT-IR and UV–visible spectroscopic analyses. Changes in the morphologies in the nanocomposites were measured using TEM and SEM techniques. The dc conductivity of POT was dramatically increased by introduction of the c-MWCNTs. The conductivity of nanocomposite was obtained in a range between 0.85 and 7.42 S cm−1 for different concentrations of c-MWCNTs. The current–voltage (I–V) characteristics of these nanocomposites indicate a significant increase in current level with an increase in c-MWCNTs concentration in the nanocomposite. I–V characteristics plotted on a log-log scale showed that the charge transport mechanism is governed by Ohm's law. In addition, the increase of conductivity with respect to temperature revealed the semiconductor behavior of the nanocomposite.

• Synthesis of COOH-functionalized MWCNT doped poly(o-toluidine) nanocomposites is discussed. • The morphological structure, FT-IR, UV–visible absorption spectra are presented. • Small amount of MWCNT incorporation leads the significant enhancement in conductivity and current level. • The increase of temperature has little effect on the conductivity of nanocomposite at low temperature region.