c,T-Dependence of the viscosity and the self-diffusion coefficients in some aqueous carbohydrate solutions

Slowing down of water dynamics in disaccharide aqueous solutions

“…3. The computed D w compare well with the diffusion coefficients interpolated from the experimental data of Mills [41] for pure water and of Rampp et al [39] for trehalose solutions, thereby suggesting that the influence of sugars on water dynamics is rather well reproduced in the present simulations. Water diffusion is slowed down by more than one order of magnitude when sugar concentration increases from 4 to 66 wt %.…”

“…Then, D w is found the lowest in the trehalose solution, as could be expected from its larger hydration number [18,26,27]. [41] for pure water and from Rampp et al [39] in 10, 30, 50 and 60 wt % trehalose solutions are also reported as a triangle and stars symbols, respectively.…”

“…Furthermore, the concomitant increase in the frequency position of the two bands indicates that the local environments experienced by water molecules are stiffer in presence of sugars, in line with the sterical restriction imposed by their rather rigid skeletons [39]. In particular, the sugar-induced blue shift of the second band implies that water-water HBs are strengthened, as will be shown more explicitely in section 3.3. properties of disaccharide/water solutions [27,28].…”

“…This shows that the slowing down of water dynamics stems from the increasing number of water-sugar HBs as sugar concentration increases. Indeed, carbohydrates induce a significant decrease of the translational and rotational diffusion coefficient of water in their hydration shell [20], as could be expected from their significantly smaller diffusion coefficient with comparison to water [39]. The steep decrease of D w when the sugar concentration increases from 49 to 66 wt % can be ascribed to the percolation of the HBN of sugars in this concentration range [27].…”

Freezing Properties of Disaccharide Solutions: Inhibition of Hexagonal Ice Crystal Growth and Formation of Cubic Ice

“…These results show that the relation between η and C is fitted by both models within the experimental conditions. (Matsuoka et al, 2002), open inverted triangles (Magazù et al, 1999), ×-marks (Elias & Elias, 1999), and +-marks (Rampp et al, 2000). (Reprinted from Uchida et al, 2009, with permission from Elsevier.…”