Large apparent slip at a moving contact line

Qian, Baoliang; Park, Joonsik; Breuer, Kenneth S.

doi:10.1063/1.4931915

Cited by 17 publications

(11 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Spreading of droplets in the partial-wetting regime can therefore serve as an alternative test for the height-dependence of surface tension; we have shown that our new model allows investigations of the spreading process without the need for precursor films (Pahlavan et al 2015). Visualization of the contactline motion at micro/nano-scales (Chen et al 2014;Qian et al 2015;McGraw et al 2016;Deng et al 2016) could therefore lead the way in refining and validating models for interfacial flows.…”

Section: Discussionmentioning

confidence: 99%

Thin films in partial wetting: stability, dewetting and coarsening

et al. 2018

View full text Add to dashboard Cite

A uniform nanometric thin liquid film on a solid substrate can become unstable due to the action of van der Waals (vdW) forces. The instability leads to dewetting of the uniform film and the formation of drops. To minimize the total free energy of the system, these drops coarsen over time until one single drop remains. Here, using a thermodynamically consistent framework, we derive a new model for thin films in partial wetting with a free energy that resembles the Cahn–Hilliard form with a height-dependent surface tension that leads to a generalized disjoining pressure, and revisit the dewetting problem. Using both linear stability analysis and nonlinear simulations we show that the new model predicts a slightly smaller critical instability wavelength and a significantly (up to six-fold) faster growth rate than the classical model in the spinodal regime; this faster growth rate brings the theoretical predictions closer to published experimental observations. During coarsening at intermediate times, the dynamics become self-similar and model-independent; we therefore observe the same scalings in both the classical (with and without thermal noise) and new models. Both models also lead to a mean-field Lifshitz–Slyozov–Wagner (LSW)-type droplet-size distribution at intermediate times for small drop sizes. We, however, observe a skewed drop-size distribution for larger drops in the new model; while the tail of the distribution follows a Smoluchowski equation, it is not associated with a coalescence-dominated coarsening, calling into question the association made in some earlier experiments. Our observations point to the importance of the height dependence of surface tension in the early and late stages of dewetting of nanometric films and motivate new high-resolution experimental observations to guide the development of improved models of interfacial flows at the nanoscale.

show abstract

Section: Discussionmentioning

confidence: 99%

Thin films in partial wetting: stability, dewetting and coarsening

et al. 2018

View full text Add to dashboard Cite

show abstract

“…45,46 Qian et al measured the liquid velocities near the substrate in the vicinity of the contact lines using particle image velocimetry and flood illumination. 47 Since surfactants change the hydrodynamic boundary condition at the liquid-gas interface of liquids, 26,27,48 surface velocimetry has been carried out. Studies using plates withdrawn from a liquid pool with surfactant solutions reveal a strong impact of the contact line velocity on the surface flow.…”

Section: Introductionmentioning

confidence: 99%

Flow profiles near receding three-phase contact lines: influence of surfactants

et al. 2021

View full text Add to dashboard Cite

show abstract

“…where the slip velocity is significantly larger than that of a small partial slip in the inner liquid-solid interface. 51,52 Since this distinct slip is only found to occur within a length scale of nanometers around the contact line, a single Navier slip model can provide overall good results if the characteristic scale of a simulation is much larger than this width of CL region. However, if the scale of simulated system is below sub-micro meter, the particular slip for the CL region becomes more dominant, at which the single Navier slip model would fail on quantifying the speed of dynamic wetting unless an artificial large slip length is used.…”

Section: Slip Boundary Condition Based On the Molecular Kinetic Theorymentioning

confidence: 99%

A multiscale volume of fluid method with self-consistent boundary conditions derived from molecular dynamics

et al. 2021

View full text Add to dashboard Cite

Molecular dynamics (MD) and volume of fluid (VOF) are powerful methods for the simulation of dynamic wetting at the nanoscale and macroscale, respectively, but the massive computational cost of MD and the sensitivity and uncertainty of boundary conditions in VOF limit their applications to other scales. In this work, we propose a multiscale simulation strategy by enhancing VOF simulations using self-consistent boundary conditions derived from MD. Specifically, the boundary conditions include a particular slip model based on the molecular kinetic theory for the three-phase contact line to account for the interfacial molecular physics, the classical Navier slip model for the remaining part of the liquid-solid interface, and a new source term supplemented to the momentum equation in VOF to replace the convectional dynamic contact angle model. Each slip model has been calibrated by the MD simulations. The simulation results demonstrate that with these new boundary conditions, the enhanced VOF simulations can provide consistent predictions with full MD simulations for the dynamic wetting of nanodroplets on both smooth and pillared surfaces, and its performance is better than those with other VOF models, especially for the pinning-

show abstract

Large apparent slip at a moving contact line

Cited by 17 publications

References 29 publications

Thin films in partial wetting: stability, dewetting and coarsening

Thin films in partial wetting: stability, dewetting and coarsening

Flow profiles near receding three-phase contact lines: influence of surfactants

A multiscale volume of fluid method with self-consistent boundary conditions derived from molecular dynamics

Contact Info

Product

Resources

About