Abstract
The structural relaxation in water solutions of kosmotrope (structure maker) and chaotrope (structure breaker) salts, namely sodium chloride, potassium chloride, and cesium chloride, were studied through quasielastic neutron scattering measurements. We found that the collective dynamics relaxation time at the structure factor peak obtained using heavy water solutions shows a distinctively different behavior in the kosmotrope as opposed to the chaotrope solutions, increasing with the salt concentration in the former and decreasing in the latter. In both cases the trends are proportional to the concentration dependence of the relative viscosity of the solutions. These results indicate that kosmotropes and chaotropes influence the solution's viscosity by impacting in opposite ways the hydrogen bond network of water, strengthening it in one case and softening it in the other.
| Original language | English |
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| Pages (from-to) | 8970-8975 |
| Number of pages | 6 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 11 |
| Issue number | 21 |
| DOIs | |
| State | Published - Nov 5 2020 |
Funding
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division, under Award Number DE-SC0014084. A.F. acknowledges support by the National Science Foundation under Agreement No. DMR-1508249. The neutron scattering experiments at Oak Ridge National Laboratory’s (ORNL’s) Spallation Neutron Source (SNS) were supported by the Scientific User Facilities Division, Office of Science (Basic Energy Sciences), U.S. Department of Energy (DOE).