Formation of multifunctional nanocomposites with ultrathin layers of polyaniline (PANI) on silver vanadium oxide (SVO) nanospheres by in situ polymerization

Abstract

We designed and successfully synthesized nanocomposites (NCs) of silver vanadium oxide nanospheres dispersed in different ultrathin layers of polyaniline (PANI–β-AgVO3) at different temperatures (60 and 80 °C) by in situ chemical oxidative polymerization for the first time. X-ray diffraction (XRD) shows a monoclinic crystallographic form of silver vanadium oxide (SVO) to be dispersed in ultrathin layers of PANI. Morphological studies were performed by field emission electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM). The NCs synthesized at temperatures of 60 and 80 °C show approximately 4 and 2 nm ultrathin layers of PANI grown on SVO nanospheres, respectively. The sizes of the SVO nanospheres dispersed in the ultrathin PANI layers are in the range of 10–40 nm. Fourier transformed infrared (FTIR) spectroscopic and energy dispersive X-ray (EDAX) spectroscopic investigations indicate the existence of SVO in the PANI layer. The NCs are further characterized by ultra violet-visible (UV-vis) spectroscopy. The electrochemical study of (PANI–β-AgVO3) shows an enhancement in the capacitance (365.6 F g−1) compared to V2O5·nH2O–PANI NCs (217.5 F g−1) and PANI (33 F g−1). The SVO dispersed in a layer of PANI NC exhibits excellent humidity sensing characteristics. The response and recovery times are found to be 4 and 8 seconds, respectively. The NCs have good potential as supercapacitors as well as in fast responsive humidity sensors. Layers of PANI on SVO are for the first time studied and correlated by XRD, Raman spectroscopy, AFM and HRTEM studies.