Cyclic Aging Conditions Research Articles

DC electrical conductivity retention and electrical compensation of polyaniline by TiO2 at higher loading percentages in polyaniline@TiO2 nanocomposites

Electrically conductive HCl-doped polyaniline (Pani)@titanium dioxide (TiO ) nanocomposites were prepared by the in-situ oxidative polymerization of aniline in the presence of different amounts of TiO nanoparticles. The synthesized Pani@TiO nanocomposites were characterized by transmission electron microscopy, X-ray diffraction, UV-visible spectroscopy, and thermogravimetric analysis. The stability of the Pani@TiO nanocomposites in terms of their electrical conductivity retention was examined under isothermal and cyclic aging conditions, and compared with that of pure Pani. The Pani@TiO nanocomposites showed higher thermal stability than pure Pani. The effect of competitive doping/de-doping by TiO was examined at different Pani to TiO weight ratios. TiO at a higher weight percentage was found to be involved in the de-doping type of interaction with Pani, leading to its neutralization, which was found to be similar to the dedoping phenomenon, as in the case of neutralization in basic media. The novel mechanism for this de-doping type of interaction of TiO with Pani has also been proposed.

Thermal Stability of Electrical Properties and Amine Vapour Sensitivity of In-Situ Prepared Polyaniline/Graphene Nanocomposites Assisted by Sodium Dodecyl Sulfate Micelles

Polyaniline (Pani)/graphene (GN) nanocomposites were prepared by in-situ oxidative polymerization of aniline with GN in presence of sodium dodecyl sulfate. The effects of polymerization and modification of the chemical structures in the nanocomposites were characterized by fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM) and X-ray diffraction techniques (XRD). Sodium dodecyl sulfate played the role of a surfactant, improving the dispersion of GN within the polymer matrix simultaneously. FTIR results revealed the presence of π-π interactions between Pani and GN leading to the formation of a charge-transfer complex. The thermal stabilities of the electric properties of the as-prepared nanocomposites were investigated as a function of GN content. As-prepared Pani/GN nanocomposites showed greater electrical conductivity as well as improved thermal stability in terms of DC electrical conductivity retention under isothermal and cyclic ageing conditions compared with pure Pani. They were also observed to possess better amine sensing properties in comparison to pure Pani when exposed to the vapour of methylamine.

Ammonia vapor sensing and electrical properties of fibrous multi-walled carbon nanotube/polyaniline nanocomposites prepared in presence of cetyl-trimethylammonium bromide

Electrically conductive HCl-doped multi-walled carbon nanotube (MWCNT)/polyaniline (Pani) nanocomposites were prepared in the presence of cetyl-trimethylammonium bromide by in situ oxidative polymerization of aniline containing different amount of MWCNTs. Thus prepared Pani@MWCNT nanocomposites were characterized by FTIR, XRD, Raman spectroscopy, SEM and TEM. The stability in terms of their electrical conductivity retention was studied under isothermal and cyclic aging conditions. Pani@MWCNT nanocomposites showed increased thermal stability in terms of DC electrical conductivity retention with increasing MWCNT content. One of the Pani@MWCNT nanocomposites was also tested for ammonia sensing which showed good sensing response and high reproducibility.