Structural changes in ethanol–water mixtures: Ultrasonics, Brillouin scattering and molecular dynamics studies

Micro-heterogeneity versus clustering in binary mixtures of ethanol with water or alkanes

“…Ethanol-water mixtures were previously studied using computer simulations in our group. [11][12][13] There is a major difference in clustering between ethanol and water. Neat ethanol contains specific clusters in the form of chains and loops, much like methanol.…”

“…22 We have used N = 160 00 particles in order to have a good description of the domain structure. In our previous analysis, [11][12][13] we used mostly N = 2048 particles, which were sufficient to obtain many thermodynamic properties, but clearly insufficient to determine long range domain oscillations in the correlation functions. The initial configurations were all started using the very convenient PackMol code.…”

“…Since in all the classical force field representation of the interactions, the values of the partial charges of water are larger than those of the ethanol hydroxyl group, water molecules are found to generally prefer to hydrogen bond with themselves, rather than with ethanol. [11][12][13] This competition tends to destroy the chain-like structure of the ethanol clusters, making these rather fuzzy aggregated structures. In ethanol-alkane mixtures, the hydroxyl groups of ethanol are hidden inside the ethanol clusters, 10 while in water, these groups are rather dispersed.…”

A comparison of force fields for ethanol–water mixtures

“…The local immiscibility of the components in these mixtures is often related to the highly non-trivial changes with the concentration of various properties, such as excess enthalpy, [25] speed of sound, [26,27] isothermal compressibility, [28] isentropic compressibility, [29] excess heat capacity [30 -32] and vapour -liquid equilibrium mole fraction curve. [33] The underlying structural organisation is due to the subtle compensation of the competing hydrophobic -hydrophilic interactions.…”

Carbon and carbon composites obtained using deep eutectic solvents and aqueous dilutions thereof

“…), polymers (PEG), and even hydrated salts with either water or organic solvents. [61][62][63][64][65][66][67][68][69][70] In all these mixtures, the plot of hypersonic velocity (v H , obtained from Brillouin measurements) versus the mole fraction of the co-solvent (w) revealed the existence of deviation from the ideal behaviour. This deviation depends on the nature of the co-solvent and it is reflected in the shape plot, e.g., displaying a maximum or a minimum when the co-solvent is a small molecule, or exponentiallike when the co-solvent is a polymer, and hence, is more prone to forming a continuous H-bond network (Fig.…”