Synthesis of gold/poly(methyl methacrylate) hybrid nanocomposites

This paper presents a method for the preparation of spherical gold/poly(methyl methacrylate) (PMMA) hybrid nanocomposites. Analysis of data from both transmission electron microscopy images and Fourier transfer infrared spectra confirm the formation of hybrid composites in which large numbers of gold nanoparticles are dispersed throughout the PMMA matrix. The diameters and dispersions of the gold nanoparticles are controlled by the polymer concentration. Gold/PMMA nano-ball composites are formed at concentrations of the polymer of ca. 35 μM (ca. 5.25 mM with respect to the repeating MMA units). In the absence of the polymer, most of the gold particles undergo macroscopic precipitation, which indicates that the PMMA polymer is essential for stabilizing the gold particles. In addition, we found that the glass-transition temperature (Tg) of the gold/PMMA nanocomposite is lower than that of the bulk PMMA polymer. After heat treatment, nanostructured networks of gold/PMMA nanocomposites can be synthesized at temperatures below the Tg of the bulk PMMA polymer. These phenomena suggest that nanocomposites can be used to engineer polymers at relatively low treatment temperatures.