Effect of Adding a Thiol Stabilizer on Synthesis of Au Nanoparticles by Sputter Deposition onto Poly(ethylene glycol)

Abstract

Abstract We previously developed a new method that combines sputter deposition of Au and the use of a capture medium of poly(ethylene glycol) (PEG) for preparing Au nanoparticles (AuNPs). To further control the size and shape of AuNPs, we improved the method in the present study by adding a low-molecular-weight α-methoxy-ω-thiopoly(oxyethylene) (mPEG-SH) as a nonvolatile stabilizing agent to PEG. The synthesized AuNPs were structurally characterized by transmission electron microscopy, small-angle X-ray scattering, and UV–vis absorption spectroscopy, and the results were compared with our earlier findings of AuNPs prepared in neat PEG. The AuNPs prepared with the addition of mPEG-SH were spherical. The concentration of mPEG-SH played an important role in controlling the size and size distribution of AuNPs, whereas the temperature of the capture medium had a small effect on these characteristics. In addition, heat treatment stability of AuNPs and the effect of elapsed time on AuNP formation were investigated; AuNPs synthesized in PEG solution containing mPEG-SH were much more resistant to the variables than AuNPs synthesized in neat PEG.