Rheological Properties of Water Films Nanoconfined in Parallel Au Plates by Molecular Dynamics Simulations

2007 ◽  
Vol 121-123 ◽  
pp. 1109-1114
Author(s):  
M.L. Liao ◽  
Shin Pon Ju ◽  
Jenn Sen Lin ◽  
Y.S. Lin
Keyword(s):  
Molecular Dynamics ◽  
Shear Rate ◽  
Molecular Dynamics Simulations ◽  
Rheological Properties ◽  
Shear Viscosity ◽  
Water Film ◽  
Water Molecules ◽  
Water Films ◽  
Dynamics Simulations ◽  
And Diffusion

Rheological properties of water films nanoconfined in two parallel Au plates are investigated with the aid of molecular dynamics simulations. The density distribution, velocity profile, and diffusion coefficients of the water film in a Couette flow are studied. Shear viscosity and its dependence on the shear rate of the water film are also examined in the present research. It is found that the density of the water molecules near the plates is much higher than that in the other regions. This indicates that many water molecules are adsorbed by the plates and adsorbed layers are formed in the vicinity of the plates. The diffusion of the whole film increases dramatically as the shear rate becomes greater than 1010 s-1. The shear viscosity decreases as the shear rate increases, especially for the water film with a small thickness, which indicates the shear-thinning behavior for viscosity of the nanoconfined film. Moreover, an increase in shear viscosity with a decrease in the film thickness can also be found in the present study.

A Molecular Dynamics Study for Stability of Thin Water Films on Nanostructured Surfaces

2015 ◽  
Author(s):  
Liyong Sun ◽  
Jun Zhou
Keyword(s):  
Molecular Dynamics ◽  
Film Thickness ◽  
Molecular Dynamics Simulations ◽  
Van Der Waals Interactions ◽  
Water Molecules ◽  
Nanostructured Surfaces ◽  
Water Films ◽  
Critical Film Thickness ◽  
The Stability ◽  
Dynamics Simulations

The stability of thin water films on a variety of gold nanostructures was simulated by molecular dynamics simulations. The critical film thickness to prevent a film break-up was investigated as a function of the characteristic length of the nanostructures. Layering of water molecules adjacent to the gold substrate was observed as a result of the strong van der Waals interactions between the water molecules and the gold atoms. A model for the critical film thickness in the presence of nanostructures is developed based on the stability analysis. The model prediction is compared with molecular dynamics simulations with good agreement.

scholarly journals Origin and control of ionic hydration patterns in nanopores

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Miraslau L. Barabash ◽  
William A. T. Gibby ◽  
Carlo Guardiani ◽  
Alex Smolyanitsky ◽  
Dmitry G. Luchinsky ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Distribution Functions ◽  
Water Molecules ◽  
Surrounding Water ◽  
Ionic Hydration ◽  
Hydration Shells ◽  
Water Layers ◽  
Dynamics Simulations ◽  
And Control

AbstractIn order to permeate a nanopore, an ion must overcome a dehydration energy barrier caused by the redistribution of surrounding water molecules. The redistribution is inhomogeneous, anisotropic and strongly position-dependent, resulting in complex patterns that are routinely observed in molecular dynamics simulations. Here, we study the physical origin of these patterns and of how they can be predicted and controlled. We introduce an analytic model able to predict the patterns in a graphene nanopore in terms of experimentally accessible radial distribution functions, giving results that agree well with molecular dynamics simulations. The patterns are attributable to a complex interplay of ionic hydration shells with water layers adjacent to the graphene membrane and with the hydration cloud of the nanopore rim atoms, and we discuss ways of controlling them. Our findings pave the way to designing required transport properties into nanoionic devices by optimising the structure of the hydration patterns.

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