A mechanistic approach for the modulation of band gap of nanopolyaniline using various heterogeneous carbon nanostructures

• Published in: Polymer bulletin (Berlin, Germany) Germany), 2020-07, Vol.77 (7), p.3499-3521
• Main Authors: Kumar, Gaurav, Singh, Jyoti Prakash, Saha, Uttam, Bera, Madhab, Goswami, Thako Hari, Maji, Pradip K.
• Format: Article
• Language: English
• Subjects: Aniline; Carbon; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Comparative studies; Complex Fluids and Microfluidics; Composite materials; Electron transport; Emulsion polymerization; Energy gap; Fourier transforms; Graphene; Graphite; Infrared spectroscopy; Modulation; Multi wall carbon nanotubes; Nanocomposites; Nanomaterials; Nanoparticles; Nanostructure; Nanostructured materials; Optical properties; Organic Chemistry; Original Paper; Oxidation; Physical Chemistry; Polyethylene glycol; Polymer Sciences; Polymers; Soft and Granular Matter; Surfactants
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-019-02927-4

The present work introduces a mechanistic approach for the synthesis of nanopolyaniline (nPANI) and modulation of its band gap using various carbon nanostructured materials. Carbon-based different nanostructures, viz. graphene oxide, reduced graphene oxide and multiwall carbon nanotubes, have been incorporated in situ for the preparation of nanocomposites. Polyethylene glycol (PEG)-based non-ionic surfactant-assisted oxidative polymerization of aniline was implemented. The major concern of this study is to present a possible mechanism and chemistry for the development of the nanomaterials (nPANI and its nanocomposites) and further the effect of heterogeneous carbon nanomaterials on both types of band gaps (optical and electrochemical) of nPANI in the presence of PEG. First time a comparative study between optical and electrochemical band gap has also been done to analyze the effect of carbon nanomaterials on nPANI. The prepared samples were characterized by Field-emission scanning electron microscopy, Fourier transform-infrared spectroscopy and X-ray diffraction. Electrochemical and optical properties were assessed by cyclic voltammetry (CV) and ultraviolet–visible spectroscopy (UV–Vis), respectively. The electrochemical ( E g CV ) and optical ( E g opt ) energy gap of nPANI was evaluated as 2.74 and 2.34 eV by CV and UV–Vis quantification, respectively. It was observed that incorporation of carbon nanomaterials at lower percentage improves E g CV of nPANI to as minimum as 2.34 eV as per the CV data. Schematic energy diagram showing the band gap reduction and electron transport mechanism using CV has also been presented. Graphic abstract