Synthesis of monodisperse polymer microspheres with mercapto groups and their application as a stabilizer for gold metallic colloid

Monodisperse polymer microspheres wit functional mercapto groups on the surface were prepared from poly[(ethylene glycol dimethacrylate)-co-(2-hydroxyethyl methacrylate)], poly(EGDMA-co-HEMA), microspheres successively through esterification of the active hydroxyl groups with acryloyl chloride to introduce carbon-carbon double bonds and then the addition reaction of hydrogen sulfide to the double bond at pH 10-11. All of the polymer microspheres were characterized by scanning electron microscopy (SEM) and FT-IR spectra. The mercapto-functionalized polymer microspheres were utilized as a stabilizer for gold metallic colloids through coordination of the mercapto group on the polymer with gold metallic nanoparticles, which were prepared by the reduction of gold chloride trihydrate with sodium borohydride as the reductant. The size and morphology of the gold on the microspheres were determined to be of narrow dispersity (in the range 4-8 nm) by transmission electron microscopy (TEM).