Tangled silver nanoparticles embedded polythiophene-functionalized multiwalled carbon nanotube nanocomposites with remarkable electrical and thermal properties

Abstract

Tangled silver nanoparticles embedded layered polythiophene-functionalized multiwalled carbon nanotube ternary nanocomposite (PTCNT-COOH 300 Ag) has been prepared by ascorbic acid reduction of silver nitrate solution in presence of aqueous dispersion of polythiophene-functionalized multiwalled carbon nanotube (PTCNT-COOH) binary nanocomposites. Binary polythiophene–functionalized multiwalled carbon nanotube nanocomposites have been prepared by in-situ chemical oxidative polymerization of thiophene monomer stabilized by sodium bis(2-ethylhexyl) sulfosuccinate (AOT) micelles in presence of functionalized multiwalled carbon nanotubes (MWCNT-COOH) using ferric chloride (FeCl3) as an oxidizing agent in chloroform solvent. The structural formation and composition of binary and ternary nanocomposites have been confirmed by fourier transform infrared spectroscopy, fourier transform Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and wide angle X-ray diffraction studies. Scanning electron microscopy (SEM) studies have revealed the nanofibrous morphology in binary nanocomposites (PTCNT-COOHs), whereas in ternary nanocomposite (PTCNT-COOH 300 Ag), silver nanoparticles were densely embedded as nanoparticles over nanofibrous structure. Transmission electron microscopic (TEM) images have provided the evidence regarding silver nanoparticles that existed in a tangled state over the nanofibrous structure. Stable dispersion of binary nanocomposites (PTCNT-COOHs) in water, ethanol and chloroform enabled us to record the UV–visible absorption spectra which have shown two peaks at 260 nm and 360 nm corresponding to π-π* transition from aromatic rings and π-polaron absorption of polythiophene respectively. On the other hand, ternary nanocomposite have shown surface plasmon resonance as broad peak tailing to 550 nm. The electrical conductivity of nanocomposites PTCNT-COOH 100 (binary nanocomposite), PTCNT-COOH 200 (binary nanocomposite), PTCNT-COOH 300 (binary nanocomposite), pristine MWCNT, functionalized MWCNT-COOH, MWCNT-COOH Ag (binary nanocomposite) and PTCNT-COOH 300 Ag (ternary nanocomposite) were 4.42 × 10−2, 5.30 × 10−1, 1.64, 8.66, 2.80, 12.40 and 80.76 S/cm respectively. The enhanced electrical conductivity of ternary nanocomposite was due to the effective charge transport through polythiophene layer which act as conductive bridge between multiwalled carbon nanotube and silver nanoparticles. Thermogravimetric analysis have revealed that high thermal stability of ternary silver nanocomposite of PTCNT-COOH 300 Ag up to 620 °C for 10% weight loss. Silver nanoparticles embedded ternary nanocomposite in basic medium shows least leaching effect, therefore it could be potentially useful in catalytical applications.