Glass polymorphism in glycerol–water mixtures: I. A computer simulation study

Abstract

Computer simulations of glassy water–glycerol mixtures: molecular structure and density during the pressure-induced amorphous–amorphous (LDA–HDA) transformation.

Glass polymorphism and liquid–liquid phase transition in aqueous solutions: experiments and computer simulations

“…That is, we interpret these observations in the sense that the sample formed at high pressure by PIA consists of MFCS and HDA, which upon decompression converts to MFCS and LDA, where the LDA contains glycerol molecules, such that the LDA density significantly increases with increasing x. We note that our earlier experiments 224 and MD simulations, 253 as well as available experimental results 230,244,254 confirm that glycerol is soluble both in LDA and HDA. These observations are in striking contrast to LiCl-H 2 O: whereas the difference in step height is slightly overestimated for LiCl-H 2 O (see double headed arrows in Fig.…”

“…This can be explained by considering that (i) there are water molecules in the solution that do not exhibit polyamorphism (see Section 3.1.1), e.g., water molecules located in the interphase (between MFCS and water domains), or (ii) by a smaller density difference between the LDA and HDA water domains within the glycerol-water than in the case of pure water. Our MD simulations show that adding glycerol considerably increases the density of the LDA solution while barely changing the density of the HDA solution, 253 supporting scenario (ii). Scenario (i) seems unlikely, since one would need more water molecules trapped in the interphase than in the MFCS.…”

“…230 Regarding the decompression-induced HDA -LDA transitions, the simulations in ref. 253 show that this transformation is very smooth in glycerol-water mixtures, barely detectable at T 4 120 K, and occurs at negative pressures. At comparable conditions, T E 140-155 K and x o 0.10-0.12, the experiments of ref.…”

“…In a recent work, we employed MD simulations to study the pressure-induced LDA -HDA transformations in glycerol-water mixtures. 253 Specifically, we studied the pressure-induced LDA -HDA transformation at various temperatures using the TIP4P/2005 water model and two glycerol models. The TIP4P/2005 water model exhibits a relatively sharp LDA -HDA transformation at low temperatures reproducing qualitatively the LDA -HDA transformation found in experiments.…”

Liquid-liquid separation of aqueous solutions: A molecular dynamics study

“…There are several theoretical and computational studies of the phase behavior of supercooled aqueous solutions. [54][55][56][57][58][59][60][61][62] Paschek calculated the excess chemical potential of Ar in TIP5P-E water using the particle insertion method and found that the solubility of Ar in LDL is much higher than that in HDL. 62 Le and Molinero performed MD simulations of an aqueous solution of hydrophilic particles using a coarse-grained model.…”