Fig. 3: Molecular dynamic behavior of PGs with respect to the DB and molecular concentrations.
From: Janus regulation of ice growth by hyperbranched polyglycerols generating dynamic hydrogen bonding
Liquid water, growing ice, and PGs were represented by transparent sky blue, plain sky blue, and green colors, respectively. a Final configuration of ice-growth simulation of pure water (first column), hbPG at low (second column) and high (third column) concentrations, and linPG at low (fourth column), and high (fifth column) concentrations. b Density profiles of water molecules (black line) and PGs (red line) along the freezing direction. The selected region (blue area) represents the region of the quasi-liquid layer. c Two-dimensional density mapping of the water molecules. The red and green colors represent the highest local density (2 g/cm3) and 1 g/cm3 of local density, respectively. The blue region in the liquid water is a low-density region owing to the presence of PG molecules. In the ice layer, the vacuum (low-density region) arises from the lattice of H2O molecules. The quasi-ordered structure of water molecules is indicated by a white circle in hbPG (low c). d DP distribution for pure water (black line), hbPG (red line), and linPG (green line) In the DP distribution for pure water, the lower 5% is the most immobile (MI) region (blue area), and the top 5% is the most mobile (MM) region (red area). e Diffusion coefficient of the surrounding water molecules according to the distance from the PG molecule. f H-bonding analysis in terms of the average number and lifetime of the H-bonds. g Proportion of multiple H-bonds between PG and its surrounding water molecules.
