The effect of PEG encapsulated silver nanoparticles on the thermal and electrical property of sonochemically synthesized polyaniline/silver nanocomposite

An investigation of microstructure of polyaniline nanocomposite is presented. The highly stable, semiconducting polyaniline/silver nanocomposites are prepared in-situ, employing the acoustic cavitation mechanism to obtain the composite in nanophase. The materials are characterized by UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), thermogravimetric analyzer (TGA) and fourier transform infrared spectroscopy (FTIR). The polyaniline nanocomposites have an extended conformation in N-methyl-2-pyrrolidinone (NMP), as seen from UV-vis spectra. The plasmon resonances for silver nanoplates are also seen. A high thermal stability is observed for the polyaniline/silver nanocomposites which increased with increasing silver content. The TEM studies show that the polyaniline is formed as nanofibers, with plate-like metallic silver nanoparticles (50 nm x 35 nm in dimension) embedded into them. From the electrical conductivity measurements of pure polyaniline and its nanocomposites it was found that incorporation of polyethylene glycol stabilized silver nanoparticles leads to increased intermolecular charge hopping that results in enhanced electrical conductivity of the nanocomposites. TGA and DSC results indicated greater thermal stability for the nanocomposites along with higher crystallinity. A study of spreading resistance of the materials, done using scanning spreading resistance microscope, revealed localized sites of high and low conductivity within the polyaniline. The low conducting sites were fewer in the case of nanocomposites.