The use of solvent relaxation NMR to study colloidal suspensions

Abstract

Solvent relaxation nuclear magnetic resonance has been widely used to study the interactions of polymers and surfactants with nanoparticles, an important area of research for use in a range of industrial formulations, especially with regards to competition effects between components. The ability of the solvent relaxation technique to distinguish between solvent molecules at the surface and those in the bulk solution has been used to obtain valuable information on the interfacial interactions and structure.We focus on systems containing combinations of polymer, surfactant and colloidal particles and illustrate how solvent relaxation measurements have addressed problems of stabilisation, flocculation and depletion in both academically and industrially relevant systems.

Supramolecular Amino Acid Based Hydrogels: Probing the Contribution of Additive Molecules using NMR Spectroscopy

“…Further insight into gelation mechanisms and molecular motional states was obtained by 1 H solution‐state NMR longitudinal relaxation times ( T 1 ) measured during the gel‐to‐solution transitions of single and multi‐component hydrogels (Figures and S 10). VT NMR measurements of 1 H T 1 times indicate the systems are in the “fast tumbling regime”, also corroborated by the decreased line widths with increasing temperature . Three distinct stages in the transformation of the hydrogels were identified during variable temperature measurements of 1 H T 1 times.…”

Self‐Assembly and Neurotoxicity of β‐Amyloid (21–40) Peptide Fragment: The Regulatory Role of GxxxG Motifs

“…Based on this hypothesis, the peptide-solvent interactions during aggregation were monitored using an efficient adaptation of solvent relaxation NMR technique. [32] This technique measured the T 2 of water using a Carr-Purcell-Meiboom-Gill (CPMG) [33] sequence ( Figure S9) at different time points in the aggregation pathway. So we performed the solvent relaxation experiments of both the peptides AV20, and G37 L and the solvent relaxation behavior for the two peptides showed distinct water dynamics during fibrillation ( Figure 5).…”

Structural and Dynamic Properties of Amorphous Solid Dispersions: The Role of Solid-State Nuclear Magnetic Resonance Spectroscopy and Relaxometry

“…Fast relaxation at a surface exposed to the dissolution media can be separated by the faster spatial NMR dynamics . Various competing processes involving the interaction of dissolution media with the dissolving particles such as polymer adsorption, desorption from the nanocrystals can be probed using solvent relaxation NMR studies . In addition, wettability measurement of amorphous systems and ASD, in general, by conventional contact angle method is challenging as the probe liquid droplet is instantaneously absorbed by the hydrophilic excipient matrix before wetting equilibrium is attained.…”