Electrical Conductivity, Isothermal Stability, and Ammonia-Sensing Performance of Newly Synthesized and Characterized Organic–Inorganic Polycarbazole–Titanium Dioxide Nanocomposite

Abstract

Electrically conductive polycarbazole−titanium dioxide nanocomposite (PCz/TiO 2 ) have been synthesized for the first time by in situ chemical oxidative polymerization of carbazole (Cz) in the presence of titanium dioxide (TiO 2 ) nanoparticles. FTIR, SEM, TEM, XRD, TGA, and DTA were used to characterize PCz/TiO 2 nanocomposites. The characterization results confirmed that there is a strong interaction between PCz and TiO 2 nanoparticles and the nanocomposites showed higher thermal stability than pure PCz. The composite showed electrical conductivity and isothermal stability in terms of DC electrical conductivity retention under ambient condition below 100 °C. A nanocomposite-based sensor was fabricated for the detection of aqueous ammonia, it was found that the resistivity of the nanocomposites increases on exposure to ammonia at room temperature (25 °C), and it showed a linear relationship between the responses and the concentration of ammonia. The comperative antimicrobial activities of PCz, its PCz/TiO 2 -7 nanocomposite and ciprofloxacin drug with different bacteria have also been studied.

DC electrical conductivity and rate of ammonia vapour-sensing performance of synthetic polypyrrole–zirconium(IV) phosphate cation exchange nanocomposite

“…PPy-ZrP nanocomposites were prepared by in situ chemical oxidative polymerization [5][6][7][8] of pyrrole in the presence of ZrP particles. A schematic representation of the formation of PPy-ZrP nanocomposite is shown in Scheme 1.…”

“…DC electrical conductivity of the nanocomposite was measured using a four-in-line probe. The conductivity (r) was calculated using the following equations [5][6][7][8] …”

“…The values of the saturated vapor pressure were obtained from Lange's handbook of chemistry by John A. Dean, Fifteenth Edition, Mc Graw-Hill, Inc. [27].Taking into account of some other ammoniasensing composite materials like Polypyrrole graphitic nanocomposite [28], Polypyrrole/Metal Sulphide nanocomposite [29], poly(3-methythiophene)-titanium(IV) molybdophosphate cation exchange nanocomposite [6] and polyaniline-titanium(IV) phosphate cation exchange nanocomposite [8] reported earlier and compared with PPy-ZrP for ammonia sensing, the following observation can be noted (Fig. 10).…”

“…In addition, polypyrrole is one of the most familiar conducting polymers that show many advantages in recombining millimicron particles to give nanocomposites [4]. Nanocomposite show new properties due to synergism between the constituents [5][6][7][8][9][10] and more available surface. Because of the new properties, nanocomposites may find applications in various fields such as device fabrication [11], photo catalysis [12], solar cells [13], fuel cell [14], biomedical and sensing application [15].…”

“…[17]. However, conducting polymer-based ion exchangers with polyvalent sites have been poorly reported in the field of gas sensing [6][7][8].…”