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Mechanistic Insight into Nanoparticle Surface Adsorption by Solution NMR Spectroscopy in an Aqueous Gel

TitleMechanistic Insight into Nanoparticle Surface Adsorption by Solution NMR Spectroscopy in an Aqueous Gel
Publication TypeJournal Article
Year of Publication2017
AuthorsEgner, TK, Naik, P, Nelson, NC, Slowing, II, Venditti, V
JournalAngewandte Chemie-International Edition
Volume56
Pagination9802-9806
Date Published08
Type of ArticleArticle
ISBN Number1433-7851
Accession NumberWOS:000406798700025
Keywordsadsorption, analysis, atomic-resolution dynamics, chemistry, dark-state, desorption, dispersion, exchange, groel, nanoparticles, NMR-invisible states, surface
Abstract

Engineering nanoparticle (NP) functions at the molecular level requires a detailed understanding of the dynamic processes occurring at the NP surface. Herein we show that a combination of dark- state exchange saturation transfer (DEST) and relaxation dispersion (RD) NMR experiments on gel-stabilized NP samples enables the accurate determination of the kinetics and thermodynamics of adsorption. We used the former approach to describe the interaction of cholic acid (CA) and phenol (PhOH) with ceria NPs with a diameter of approximately 200 nm. Whereas CA formed weak interactions with the NPs, PhOH was tightly bound to the NP surface. Interestingly, we found that the adsorption of PhOH proceeds via an intermediate, weakly bound state in which the small molecule has residual degrees of rotational diffusion. We believe the use of aqueous gels for stabilizing NP samples will increase the applicability of solution NMR methods to the characterization of nanomaterials.

DOI10.1002/anie.201704471
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