Pulsed field gradient NMR studies of polymer adsorption on colloidal CdSe quantum dots

The Journal of Physical Chemistry. B
Lei ShenMitchell A Winnik

Abstract

Pulsed field gradient nuclear magnetic resonance (PFG NMR) experiments have been used to examine ligand exchange between poly(2-(N,N-dimethylamino)ethyl methacrylate) (PDMA) (Mn = 12,000, Mw/Mn = 1.20, Nn = 78) and trioctylphosphine oxide (TOPO) bound to the surface of CdSe/TOPO quantum dots (QDs). We show that PFG 1H NMR can quantify the displacement of TOPO by PDMA through its ability to differentiate signals due to TOPO bound to the QDs versus those from TOPO molecules free in solution. For CdSe QDs with a band edge absorption maximum at 558 nm (diameter 2.7 nm by transmission electron microscopy), we determined that, at saturation, 8 polymer chains on average displace greater than 90% of the surface TOPO groups. At partial saturation, with an average of 6 polymer chains/QD, each TOPO displaced requires 28 DMA repeat units. Assuming that one Me2N- group binds to a surface Cd2+ for each TOPO displaced, we infer that only about 3% of the DMA units are directly bound to the surface. The remaining groups are present as loops or tails that protrude into the solvent and increase the hydrodynamic diameter of the particles.

References

Oct 13, 2000·Science·V I KlimovM G Bawendi
Jul 18, 2001·Journal of the American Chemical Society·S PathakM E Thompson
Mar 30, 2002·Science·Wendy U HuynhA Paul Alivisatos
Aug 31, 2002·Science·YunWei Charles CaoChad A Mirkin
Jan 9, 2003·Journal of the American Chemical Society·Inga PotapovaAlf Mews
Mar 4, 2003·Chemical Communications : Chem Comm·Habib Skaff, Todd Emrick
Jan 6, 2004·Nature Biotechnology·Paul Alivisatos
Apr 15, 2004·Angewandte Chemie·Jonathan S SteckelMoungi G Bawendi
Jun 4, 2004·Journal of the American Chemical Society·Mia G BerrettiniGeoffrey F Strouse
May 12, 2005·Nano Letters·Randy J EllingsonAlexander L Efros

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Citations

Sep 6, 2019·Chemistry : a European Journal·Francesca ArcudiEmily Allyn Weiss
Jun 18, 2010·Journal of the American Chemical Society·Jordan W ThomsonGeoffrey A Ozin
Jul 4, 2008·Langmuir : the ACS Journal of Surfaces and Colloids·Wanjuan LinMitchell A Winnik
Jul 9, 2010·Journal of the American Chemical Society·Bernd FritzingerZeger Hens
Nov 3, 2010·ACS Applied Materials & Interfaces·Mingfeng WangMitchell A Winnik
Oct 17, 2017·Analytical Chemistry·Yongqian ZhangRobert J Hamers
Jun 24, 2020·Journal of the American Chemical Society·Cody R CarrLouise A Berben

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