Thermal and spectroscopic properties of polystyrene/gold nanocomposite containing well-dispersed gold nanoparticles.

The thermal and spectroscopic properties of polystyrene/(gold particles) (PS(SH)/Au) nanocomposite materials containing uniformly dispersed nanoparticles in a polymer matrix have been studied. The nanocomposite comprises the thiol-terminated polystyrene (PS(SH)) which was produced by capping a living polystyrene with ethylene sulfide and the nano-sized gold particles (AuNPs) which were in-situ formed in the presence of PS(SH). The PS(SH) was characterized by NMR and the bonding between thiols and AuNPs was verified by X-ray Photoelectron Spectroscopy. Based on the transmission electron microscopy and the UV-vis absorption spectra, PS(SH) with a lower molecular weight leads to the formation of bigger AuNPs. The T(D) of the nanocomposite (PS(SH)/Au) increases with an increase in the Au content and at a constant Au content the PS(SH) with a higher molecular weight affords PS(SH)/Au a higher T(D). While PS(SH)/Au has a higher T(g) than the corresponding pristine PS(SH), the difference reduces with an increase in Au content (i.e., a decrease in the PS(SH):Au weight ratio) because of the formation of larger AuNPs which provide a smaller total surface area for PS(SH) to anchor or to cover.