Synthesis of thermally stable Au-core/Pt-shell nanoparticles and their segregation behavior in diblock copolymer mixtures

Se Gyu Jang, Anzar Khan, Michael D. Dimitriou, Bumjoon J. Kim, Nathaniel A. Lynd, Edward J. Kramer, Craig J. Hawker

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

We report a facile strategy for the preparation of sub-5 nm gold/platinum (Au-Pt) nanoparticles which are thermally stabilized by a crosslinked polymer shell. Diblock copolymer (PS-b-PI-SH) ligands on the Au nanoparticles were used to crosslink the vinyl functionalities on PI via hydrosilylation with 1,1,3,3-tetramethyldisiloxane in the presence of a platinum catalyst. The Pt catalyst was reduced on the Au nanoparticles during the hydrosilylation reaction resulting in the formation of a Pt-shell on the Au nanoparticle. The hydrosilylation reaction on the Au nanoparticles as well as their positioning in films of a poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) block copolymer were thoroughly characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), UV-VIS spectroscopy, and X-ray photoelectron spectroscopy (XPS). Variables such as number of vinyl groups on PS-b-PI-SH ligands, the areal density of these ligands on the Au nanoparticle as well as the concentrations of the reactive species were varied systematically to obtain thermally stable nanoparticles. Au-Pt nanoparticles were stable in organic solvents up to 130 °C, and in polymer films at 190 °C for several days. This increased stability allowed the nanoparticles to be thermally annealed in films of PS-b-P2VP where their strong interfacial activity and localization were observed.

Original languageEnglish
Pages (from-to)6255-6263
Number of pages9
JournalSoft Matter
Volume7
Issue number13
DOIs
Publication statusPublished - 2011 Jul 7
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics

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