TY - JOUR
T1 - Molecular interpretation of the non-Newtonian viscoelastic behavior of liquid water at high frequencies
AU - Schulz, Julius C.F.
AU - Schlaich, Alexander
AU - Heyden, Matthias
AU - Netz, Roland R.
AU - Kappler, Julian
N1 - Funding Information:
We acknowledge funding from the DFG via SFB 1114, Project No. 235221301, Project C2. Work was funded in part by the European Research Council under the EU's Horizon 2020 Program, Grant No. 740269.
Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/10
Y1 - 2020/10
N2 - Using classical as well as ab initio molecular dynamics simulations, we calculate the frequency-dependent shear viscosity of pure water and water-glycerol mixtures. In agreement with recent experiments, we find deviations from Newtonian-fluid behavior in the THz regime. Based on an extension of the Maxwell model, we introduce a viscoelastic model to describe the observed viscosity spectrum of pure water. We find four relaxation modes in the spectrum which we attribute to (i) hydrogen-bond network topology changes, (ii) hydrogen-bond stretch vibrations of water pairs, (iii) collective vibrations of water molecule triplets, and (iv) librational excitations of individual water molecules. Our model quantitatively describes the viscoelastic response of liquid water on short timescales, where the hydrodynamic description via a Newtonian-fluid model breaks down.
AB - Using classical as well as ab initio molecular dynamics simulations, we calculate the frequency-dependent shear viscosity of pure water and water-glycerol mixtures. In agreement with recent experiments, we find deviations from Newtonian-fluid behavior in the THz regime. Based on an extension of the Maxwell model, we introduce a viscoelastic model to describe the observed viscosity spectrum of pure water. We find four relaxation modes in the spectrum which we attribute to (i) hydrogen-bond network topology changes, (ii) hydrogen-bond stretch vibrations of water pairs, (iii) collective vibrations of water molecule triplets, and (iv) librational excitations of individual water molecules. Our model quantitatively describes the viscoelastic response of liquid water on short timescales, where the hydrodynamic description via a Newtonian-fluid model breaks down.
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U2 - 10.1103/PhysRevFluids.5.103301
DO - 10.1103/PhysRevFluids.5.103301
M3 - Article
AN - SCOPUS:85093364921
SN - 2469-990X
VL - 5
JO - Physical Review Fluids
JF - Physical Review Fluids
IS - 10
M1 - 103301
ER -