Synthesis, characterization and dielectric studies of poly(1-naphthylamine)–tungsten disulphide nanocomposites

Abstract

Here, novel poly(1-naphthylamine)–tungsten disulphide (PNA–WS2) nanocomposites were synthesized through an in-situ chemical oxidative polymerization of 1-naphthylamine in the presence of ultrasonically dispersed WS2. The effect of WS2 addition on the optoelectrical, morphological and thermal properties of PNA was studied by using different analytical tools. SEM images revealed that PNA aggregates are well supported on the dispersed WS2 sheets. The formation of a fibrous network of PNA over the dispersed WS2 layers evidenced from the TEM images has suggested larger surface area and better interfacial interaction between PNA and incorporated WS2 layers. The thermal stability was improved upon the incorporation of WS2. Optical bandgap values of PNA–WS2 nanocomposites were lower than that of bulk WS2 and pristine PNA. Electrical and dielectric studies have confirmed an improvement in conductivity and dielectric properties with increasing WS2 content, which was credited to the better charge transport between the polar backbone of PNA and charged surface of dispersed WS2 due to enhanced interfacial area and electrostatic interactions between the components. A maximum AC conductivity of 4.4 × 10–3 Sm−1 was displayed by nanocomposite containing 20% WS2 loading and a further increase in WS2 content showed a detrimental effect in electrical and dielectric properties. The present study has demonstrated that optical and dielectric properties of composites can be readily tuned by proper control of the composition and dispersion of WS2 within the PNA matrix.