| 1. |
- Atri, Ria S., et al.
(författare)
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Morphology Modulation of Ionic Surfactant Micelles in Ternary Deep Eutectic Solvents
- 2020
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 124:28, s. 6004-6014
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Tidskriftsartikel (refereegranskat)abstract
- Deep eutectic solvents (DES) are potentially greener solvents obtained through the complexation of simple precursors which, among other applications, have been investigated in recent years for their ability to support the self-assembly of amphiphilic molecules. It is crucial to understand the factors which influence surfactant solubility and self-assembly with respect to the interaction of the surfactant molecule with the DES components. In this work, small-angle neutron scattering (SANS) has been used to investigate the micellization of cationic (CnTAB) and anionic (SDS) surfactants in a ternary DES comprising choline chloride, urea, and glycerol, where the hydrogen bond donors are mixed in varying molar ratios. The results show that in each case either globular or rodlike micelles are formed with the degree of elongation being directly dependent on the composition of the DES. It is hypothesized that this composition dependence arises largely from the poor solubility of the counterions in the DES, especially at low glycerol content, leading to a tighter binding of the counterion to the micelle surface and giving rise to micelles with a high aspect ratio. This potential for accurate control over micelle morphology presents unique opportunities for rheology control or to develop templated syntheses of porous materials in DES, utilizing the solvent composition to tailor micelle shape and size, and hence the pore structure of the resulting material.
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| 2. |
- Hammond, Oliver S., et al.
(författare)
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Neutron Diffraction Study of Indole Solvation in Deep Eutectic Systems of Choline Chloride, Malic Acid, and Water
- 2022
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 28:41
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Tidskriftsartikel (refereegranskat)abstract
- Deep eutectic systems are currently under intense investigation to replace traditional organic solvents in a range of syntheses. Here, indole in choline chloride-malic acid deep eutectic solvent (DES) was studied as a function of water content, to identify solute interactions with the DES which affect heterocycle reactivity and selectivity, and as a proxy for biomolecule solvation. Empirical Potential Structure Refinement models of neutron diffraction data showed [Cholinium]+ cations associate strongly with the indole π-system due to electrostatics, whereas malic acid is only weakly associated. Trace water is sequestered into the DES and does not interact strongly with indole. When water is added to the DES, it does not interact with the indole π-system but is exclusively in-plane with the heterocyclic rings, forming strong H-bonds with the -NH group, and also weak H-bonds and thus prominent hydrophobic hydration of the indole aromatic region, which could direct selectivity in reactions.
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