Direct characterization of polymer encapsulated CdSe/CdS/ZnS quantum dots

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DOI

  • Gilad Zorn, National ESCA and Surface Analysis Center for Biomedical Problems, The Department of Chemical Engineering.
  • ,
  • Shivang R Dave, National ESCA and Surface Analysis Center for Biomedical Problems, The Department of Bioengineering, University of Washington, Seattle, WA 98195-1653.
  • ,
  • Tobias Weidner
  • Xiaohu Gao, National ESCA and Surface Analysis Center for Biomedical Problems, The Department of Bioengineering, University of Washington, Seattle, WA 98195-1653.
  • ,
  • David G. Castner, National ESCA and Surface Analysis Center for Biomedical Problems, The Department of Chemical Engineering.

Surface engineering advances of semiconductor quantum dots (QDs) have enabled their application to molecular labeling, disease diagnostics and tumor imaging. For biological applications, hydrophobic core/shell QDs are transferred into aqueous solutions through the incorporation of water-solubility imparting moieties, typically achieved via direct exchange of the native surface passivating ligands or indirectly through the adsorption of polymers. Although polymeric encapsulation has gained wide acceptance, there are few reports addressing the characterization of the adsorbed polymers and existing theoretical analyses are typically based on simple geometric models. In this work, we experimentally characterize and quantify water-soluble QDs prepared by adsorption of amphiphilic poly(maleic anhydride-alt-1-tetradecene) (PMAT, MW~9000) onto commercially available CdSe/CdS/ZnS (CdSe/CdS/ZnS-PMAT). Using x-ray photoelectron spectroscopy (XPS) we determined that ~15 PMAT molecules are adsorbed onto each QD and sum frequency generation (SFG) vibrational spectra was utilized to investigate the mechanism of interaction between PMAT molecules and the QD surface. Importantly, when employed together, these techniques constitute a platform with which to investigate any polymer-nanoparticle complex in general.

OriginalsprogEngelsk
TidsskriftSurface Science
Vol/bind648
Sider (fra-til)339-344
Antal sider6
ISSN0039-6028
DOI
StatusUdgivet - 2016
Eksternt udgivetJa

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