1,3:2,4‐Dibenzylidene‐d‐sorbitol (DBS), a simple, commercially relevant compound, was found to self‐assemble as a result of intermolecular noncovalent interactions into supramolecular gels in deep eutectic solvents (DESs) based on choline chloride combined with alcohols/ureas. DBS formed gels at a loading of 5 % w/v. Rheology confirmed the gel‐like nature of the materials, electron microscopy and X‐ray diffraction indicated underpinning nanofibrillar DBS networks, and differential scanning calorimetry showed the DES nature of the liquid‐like phase was retained. The ionic conductivities of the gels were similar to those of the unmodified DESs, thus proving the deep eutectic nature of the ionic liquid‐like phase. Gelation was tolerant of ionic additives Li+, Mg2+, and Ca2+; the resulting gels had similar conductivities to electrolyte dissolved in the native DES. The low‐molecular‐weight gelator DBS is thus a low‐cost additive that forms gels in DESs from readily available constituents, with conductivity levels suitable for practical applications.
This paper reports the ability of 1,3:2,4-dibenzylidene-Dsorbitol (DBS), a simple, commercially-relevant compound, to selfassemble as a result of intermolecular non-covalent interactions into supramolecular gels in deep eutectic solvents (DESs). The DESs are based on choline chloride combined with alcohols/ureas -DBS forms gels at a loading of 5% wt/vol. Rheology confirms the gel-like nature of the materials, electron microscopy and X-ray diffraction indicate underpinning nanofibrillar DBS networks and differential scanning calorimetry shows the deep eutectic solvent nature of the liquid-like phase is retained. The ionic conductivities of the gels are similar to those of the unmodified DESs proving the deep eutectic nature of the ionic liquid-like phase. Gelation is tolerant of ionic additives Li + , Mg 2+ and Ca 2+ , with the resulting gels having similar conductivities to electrolyte dissolved in the native DES. The low-molecular-weight gelator DBS is a low-cost additiveforming gels in DESs from readilyavailable constituents, with conductivity levels suitable for practical applications. We suggest supramolecular eutectogels have potential uses ranging from energy technology to synthesis and catalysis.
Article:Rohner, Stefan S., Ruiz-Olles, Jorge orcid.org/0000-0002-3037-5722 and Smith, David K. orcid.org/0000-0002- 9881-2714 (2015) Speed versus stability-structure-activity effects on the assembly of two-component gels. RSC Advances.This paper reports the structural modification of a two-component gelation system comprising a 1:1 complex formed between a peptide carboxylic acid and phenylethylamine. Changing amino acids has a profound effect on the speed of gel formation and the minimum gelation concentration (MGC) yet the thermal stability of the gel remains unchanged.Variable temperature NMR studies demonstrate that at room temperature, the speed at which the gel forms is controlled by the solubility of the acid-amine complexes, which mediates the initial nucleation step required for gel assembly.On increasing the temperature, however, a thermodynamic enthalpy-entropy balance means all of the gels break down at around the same temperature. Those gels which are more favourably and rapidly formed at room temperature on enthalpic grounds are also more temperature sensitive as a consequence of the greater entropic cost of efficient packing within the gel fibres. This constitutes a rare example in which the time required for gelation can be structurally controlled, with NMR providing unique insight into the dynamics of these gel-phase materials. We suggest that in the future, combining solvent and solute (gelator) solubility parameters may provide further insight into these materials.
The diffusion of vital components of gel nanofibres across a gel–gel interface is quantified – highly dynamic, self-assembled, two-component gels can adapt and reorganise over time.
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