Water-dispersible conducting nanocomposites of binary polymer systems. I. Poly(N-vinylcarbazole)-polyaniline-Al2O3 nanocomposite system

Abstract

The chemical oxidative polymerization of a mixture of N-vinylcarbazole (NVC) and aniline (ANI), by FeCl3 in aqueous medium, produced an insoluble polymer that contained polyaniline (PANI), along with some residual poly-N-vinylcarbazole (PNVC) not extractable with benzene. This insoluble PNVC–PANI composite could be obtained as a stable suspension in water when the above polymerization was conducted in the presence of nanodimensional Al2O3. Alternatively, PNVC–(PANI–Al2O3) composite could also be produced by precipitating a THF solution of preformed PNVC onto a PANI–Al2O3 suspension. Likewise PANI–(PNVC–Al2O3) could be obtained by polymerizing ANI onto an aqueous suspension of PNVC–Al2O3. The inclusion of either of these monomer units in the resultant polymer was confirmed by FTIR analysis. SEM analyses revealed formation of a lumpy aggregate, and TEM analyses confirmed particle sizes of the PNVC–PANI–Al2O3 composite to be in the 52–200 nm range. Thermogravimetric stability was in the order: PANI–Al2O3 < PNVC–PANI–Al2O3 < PNVC–Al2O3. The dc conductivity values (S/cm) followed the trend: PNVC–Al2O3 (10−7) < PNVC–PANI–Al2O3 (1.5 × 10−4) ≈ PANI–Al2O3 (1.1 × 10−4) < PNVC–PANI (1 × 10−3) at ambient temperature. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 803–811, 2004