Conducting polyaniline-titanium dioxide nanocomposites prepared by inverted emulsion polymerization

Conducting polyaniline (PAni)-titanium dioxide (TiO₂) nanocomposites have been synthesized by the inverted emulsion polymerization method. Aqueous mixtures of aniline, a free-radical oxidant, and/or TiO ₂ nanopar- ticles (∼25 nm in diameter; mixture of anatase and ru- tile) are utilized to synthesize the hybrid nanocompo-sites. The polymerization is carried out in an organic solvent (chloroform, CHCl₃) in the presence of a pro- tonic acid (hydrochloric acid, HCl) as a dopant and an emulsifier (cetyl trimethylammonium bromide). The resultant PAni-TiO₂ nanocomposites are characterized with their structural, morphological, conducting, and optical properties. SEM and TEM images represent the PAni-TiO₂ nanocomposites with the diameter range of 50-200 nm. Electrical conductivities are checked by standard four-point probes method and found to be 0.38 S/cm for bulk PAni and 0.11 S/cm for PAni-TiO₂ nanocomposites. UV-visible absorption shows two electronic bands at about 320 and 596 nm for bulk PAni and the blue-shifted bands with the intensity changes due to the formation of PAni-TiO₂ composites. Thermogravimetric analysis reveals that the composites have a higher degradation temperature than the PAni alone. POLYM. COMPOS., 31:83-88, 2010.