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

Slowing, Igor
Egner, Timothy
Naik, Pranjali
Nelson, Nicholas
Slowing, Igor
Venditti, Vincenzo
Venditti, Vincenzo
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Ames Laboratory
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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.

<p>This is the peer reviewed version of the following article: Egner, Timothy K., Pranjali Naik, Nicholas C. Nelson, Igor I. Slowing, and Vincenzo Venditti. "Mechanistic Insight into Nanoparticle Surface Adsorption by Solution NMR Spectroscopy in an Aqueous Gel." <em>Angewandte Chemie</em> 129, no. 33 (2017): 9934-9938, which has been published in final form at DOI: <a href="" target="_blank">10.1002/ange.201704471</a>. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.</p>
Adsorption, Desorption, Nanopartikel, NMR-unsichtbare Zustände, Oberflächenanalyse