Molecular simulation and continuum mechanics investigation of viscoelastic properties of fluids confined to molecularly thin films

Khare, Rajesh; Pablo, Juan; Yethiraj, Arun

doi:10.1063/1.1361077

Cited by 28 publications

(21 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Linear shear response was simulated in an MD study of oscillatory shear flow combined with an analysis of the shear stress using continuum mechanics [14]. The results of this study proved to be in qualitative agreement with the experimental measurements by Demirel and Granick [4].…”

Section: Introductionsupporting

confidence: 65%

Nanotribology of Confined Water by Quasistatic Computer Simulations: Effect of Impurities

Pertsin

Grunze

2010

Tribol Lett

View full text Add to dashboard Cite

In our previous simulation study (Pertsin and Grunze, Langmuir 24:4750-4755, 2008), we have shown that water bilayer films confined between structured hydrophilic substrates can acquire the ability to sustain shear stress (i.e., to solidify), while remaining fluidlike in respect of the lateral order and molecular mobility. In this article, the previous simulations are extended to aqueous bilayer films containing simple model impurities. The shear behavior of the films is studied using the grand canonical Monte Carlo technique and quasistatic approach. It is found that the impurities tend to separate into an individual phase or to dissolve in water depending on the strength of the water-impurity interaction. In the former case, the effect of impurity on the shear modulus and yield stress is moderate and nearly linear in the concentration of impurity. In the latter case, the effect is noticeably stronger because the impurity distorts the local order and arrangement of water molecules, thus disturbing the local epitaxial coupling between the aqueous film and confining substrates. At the highest impurity content tried (*13%), the aqueous film loses most of its solidity and becomes practically fluidlike in respect to the shear response.

show abstract

Section: Introductionsupporting

confidence: 65%

Nanotribology of Confined Water by Quasistatic Computer Simulations: Effect of Impurities

Pertsin

Grunze

2010

Tribol Lett

View full text Add to dashboard Cite

show abstract

“…͑i͒ The volume over which the average is taken is not well defined and ͑ii͒ in calculating the local viscosity from the average density they applied the Enskog theory of hard spheres which is not applicable, in general. Khare et al 7 have studied the viscoelasticity in high density polymeric films undergoing oscillatory shear. By fitting the results of the wall shear, obtained through nonequilibrium molecular dynamics ͑NEMD͒ simulations, to the macroscopic equations they were able to investigate the storage and loss moduli as a function of frequency.…”

Section: Introductionmentioning

confidence: 99%

Local linear viscoelasticity of confined fluids

Hansen

Daivis²,

Todd³

2007

The Journal of Chemical Physics

View full text Add to dashboard Cite

In this paper the authors propose a novel method to study the local linear viscoelasticity of fluids confined between two walls. The method is based on the linear constitutive equation and provides details about the real and imaginary parts of the local complex viscosity. They apply the method to a simple atomic fluid undergoing zero mean oscillatory flow using nonequilibrium molecular dynamics simulations. The method shows that the viscoelastic properties of the fluid exhibit dramatic spatial changes near the wall-fluid boundary due to the high density in this region. It is also shown that the real part of the viscosity converges to the frequency dependent local shear viscosity sufficiently far away from the wall. This also provides valuable information about the transport properties in the fluid, in general. The viscosity is compared with predictions from the local average density model. The two methods disagree in that the local average density model predicts larger viscosity variations near the wall-fluid boundary than what is observed through the method presented here.

show abstract

“…[24,25]. The viscous heating of simple liquids in the same geometry was also studied using a full MD simulation in Refs.…”

Section: Introductionmentioning

confidence: 99%

Synchronized Molecular-Dynamics Simulation via Macroscopic Heat and Momentum Transfer: An Application to Polymer Lubrication

Yasuda

Yamamoto

2014

Phys. Rev. X

View full text Add to dashboard Cite

A synchronized molecular-dynamics simulation via macroscopic heat and momentum transfer is proposed to model the nonisothermal flow behaviors of complex fluids. In this method, the moleculardynamics simulations are assigned to small fluid elements to calculate the local stresses and temperatures and are synchronized at certain time intervals to satisfy the macroscopic heat-and momentum-transport equations. This method is applied to the lubrication of a polymeric liquid composed of short chains of ten beads between parallel plates. The rheological properties and conformation of the polymer chains coupled with local viscous heating are investigated with a nondimensional parameter, the Nahme-Griffith number, which is defined as the ratio of the viscous heating to the thermal conduction at the characteristic temperature required to sufficiently change the viscosity. The present simulation demonstrates that strong shear thinning and a transitional behavior of the conformation of the polymer chains are exhibited with a rapid temperature rise when the Nahme-Griffith number exceeds unity. The results also clarify that the reentrant transition of the linear stress-optical relation occurs for large shear stresses due to the coupling of the conformation of polymer chains with heat generation under shear flows.

show abstract

Molecular simulation and continuum mechanics investigation of viscoelastic properties of fluids confined to molecularly thin films

Cited by 28 publications

References 25 publications

Nanotribology of Confined Water by Quasistatic Computer Simulations: Effect of Impurities

Nanotribology of Confined Water by Quasistatic Computer Simulations: Effect of Impurities

Local linear viscoelasticity of confined fluids

Synchronized Molecular-Dynamics Simulation via Macroscopic Heat and Momentum Transfer: An Application to Polymer Lubrication

Contact Info

Product

Resources

About