Probing capping molecules on nanoparticles in suspension by DOSY NMR
F. Ribot, F. Guillemot, B. Dubertret, L. van Lokeren, R. Willem
UPMC Univ Paris 06, FR
Keywords: NMR, Nanoparticles, Capping molecules
Abstract:DOSY NMR is an efficient tool to characterize suspensions of nanoparticles (NPs). This technique, which gives access to diffusion coefficients, allows one to differentiate the capping molecules, which interact with nanoparticles, from the free ones. The possibilities of this technique are illustrated with three examples: cerium dioxide NPs functionalized with long chain carboxylic acids, titanium dioxide NPs prepared by hydrolysis-condensation of titanium butoxide in the presence of acetylacetone and p-toluene sulfonic acid, and CdSe quantum dots covered by trioctylphosphine oxide (TOPO) In the last case, emphasis is placed on the exchange phenomenon and the lifetime of the interacting TOPO is estimated.