Synthesis and X-ray Photoelectron Spectroscopy Studies of Poly(vinyl pyrrolidone) Capped Gold Nanoparticles in a Hybrid Nanocomposite

A polymer composite of Au-metal reinforced Npolyvinyl pyrrolidone (PVP) is synthesized in a shape of thin laminates. The process involves a direct reduction of the Au 3+ → Au 0 in presence of active PVP molecules under hot conditions in water at 60-70°C. A stabilized Au-PVP surface interface of Au-nanoparticles capping in stable PVP polymer molecules is formed. The surface regulating PVP polymer insulates the particles from Au 3+ and further aggregation. A viscous sample, after evaporating the water at 60-70°C, is casted as a film or in a shape of a thin laminate. Varying the Au-content 0.05 -1.0 wt% in AuPVP, films are studied in terms of optical absorption, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction. The Au-metal reflects in two characteristic 4f7/2 and 4f5/2 XPS bands of 83.1 and 86.8 eV respectively. The shifting of the binding energy Eb in the Au 4f peaks to a lower value relative to the bulk value confirms the microscopic interaction between the Au nanoparticles and the PVP polymer in the hybrid composites.