Fabrication of conductive cross‐linked polyaniline/G‐MWCNTS core‐shell nanocomposite: A selective sensor for trace determination of chlorophenol in water samples

Abstract

The nanocomposites (NCs) of cross‐linked polyaniline (CPA) with a variety of carbon nanomaterials (CNMs) (CPA/CNMs NCs) was prepared by the chemical oxidative copolymerization of PANI and p‐phenylenediamine (PPDA) with triphenylamine (TPA) in the presence of CNMs. The results of XRD, FTIR and Raman indicated that the CPA/CNMs NCs were effectively synthesized with strong interactions among the constituents. The morphology study demonstrated that CNMs were well coated by CPA and produce a well‐aligned nanorod core‐shell structure with the large surface area which may be more beneficial to electrical conductivity when used as electrode materials. Differential thermal analysis techniques (TGA‐DTG) were used to characterize the thermal stability of NCs. The heat of formation of CPA monomer from TPA, PPDA and aniline (ANI) were computed using Density Functional Theory (DFT) calculations. The NCs of G‐MWCNTs demonstrate higher affinity to oxidation of Chlorophenols (CPHs) than glassy carbon electrode (GCE), CPA/GCE and the other NCs. Differential pulse voltammetry (DPV) was used for the trace determination of 2,4‐dichlorophenol (2,4‐DCP). Under the optimum conditions, the peak current of 2,4‐DCP was proportional to its concentration in the range of 0.05‐0.6 μmol/L. The detection limit was 7.6 nmol/L. The method was successfully applied for the determination of 2,4‐DCP in fish farm water with satisfactory recoveries. The suggested method has an advantage to be used for water samples due to its short analytical time, rapid response, high sensitivity, and excellent selectivity with good reproducibility.