The influence of topography on dynamic wetting

Ramiasa, Melanie; Ralston, John; Fetzer, Renate; Sedev, Rossen

doi:10.1016/j.cis.2013.04.005

Cited by 109 publications

(82 citation statements)

References 161 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Predictions from MKT show agreement with experimentally observed displacement rates for different liquid pairs by assuming nanoscale defect sizes s d = 0.2-1 nm (e.g., see Ref. [16]). For consistency with the model assumptions of MKT the defect size must be smaller than 1 nm (A d ∼ 1 nm 2 ), which yields energy barriers ∆E 10 k B T (here k B is the Boltzmann constant and T the system temperature).…”

Section: Introductionsupporting

confidence: 68%

“…3) can be used to estimate the critical lengths L c below which the drainage becomes a thermally activated process and L(t) is governed by Eq. (16). For the experimental conditions in case (i) (cf.…”

Section: Resultsmentioning

confidence: 99%

“…The conventional approach to consider the effects of random surface defects with macroscopic (s d > 100 nm) or mesoscopic (s d 10-100 nm) dimensions consists in employing receding and advancing contact angles that are different from the Young contact angle θ Y , which is determined by minimization of energy on a perfectly smooth surface. Despite available predictive models based on the Wenzel [12] and Cassie-Baxter [13] equations, no analytical approach has been established to quantitatively predict the degree of contact angle hysteresis from topographic parameters characterizing the surface [3,[14][15][16]. As result, receding and advancing contact angles for static and dynamic conditions for different surfaces and liquid pairs must often be determined empirically.…”

Section: Introductionmentioning

confidence: 99%

“…In the so-called molecular kinetic theory (MKT) proposed by Blake and coworkers [27][28][29][30], the effect of atomistic and nanoscale surface defects is modeled as a frictional force that dissipates the work required for the molecules in the contact line to "hop" over energy barriers ∆E between adsorption sites separated by a distance λ s d . The virtual frictional force proposed in MKT scales linearly with viscosity and its magnitude is often comparable to hydrodynamic forces, which can make it difficult to distinguish between damping due to pinning at nanoscale defects or hydrodynamic effects [2,16,29,31]. Energy barriers ∆E = W a in MKT are determined by the "work of adhesion" W a γA d (1 + cos θ Y ) at localized sites, here γ is the liquid-vapor surface tension γ and A d ∼ s 2 d the area of the adsorption site.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Crossover from shear-driven to thermally activated drainage of liquid-infused microscale capillaries

et al. 2016

View full text Add to dashboard Cite

The shear-driven drainage of capillary grooves filled with viscous liquid is a dynamic wetting phenomenon relevant to numerous industrial processes and novel lubricant-infused surfaces. Prior work has reported that a finite length L∞ of the capillary groove can remain indefinitely filled with liquid even when large shear stresses are applied. The mechanism preventing full drainage is attributed to a balance between the shear-driven flow and a counterflow driven by capillary pressures caused by deformation of the free surface. In this work, we examine closely the approach to the final equilibrium length L∞ and report a crossover to a slow drainage regime that cannot be described by conventional dynamic models considering solely hydrodynamic and capillary forces. The slow drainage regime observed in experiments can be instead modeled by a kinetic equation describing a sequence of random thermally activated transitions between multiple metastable states caused by surface defects with nanoscale dimensions. Our findings provide new insights on the critical role that natural or engineered surface roughness with nanoscale dimensions can play in the imbibition and drainage of capillaries and other dynamic wetting processes in microscale systems.

show abstract

Section: Introductionsupporting

confidence: 68%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Crossover from shear-driven to thermally activated drainage of liquid-infused microscale capillaries

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The characteristic size λ M of the adsorption sites is treated as a free parameter that must, however, remain within molecular dimensions (i.e., λ M < 1 nm) for consistency with the premises of MKT. 43 As discussed in detail later in Sec. III C, maximum friction coefficients ξ s (z = 0) = O(0.1-1 µN s/m) predicted by MKT for λ M = 0.5-1 nm produce dissipative forces that are two to three orders of magnitude smaller than those required to describe the experimentally observed adsorption dynamics.…”

Section: B Dissipative Forcesmentioning

confidence: 99%

Colloidal particle adsorption at liquid interfaces: capillary driven dynamics and thermally activated kinetics

Rahmani¹,

Wang²,

Manoharan³

et al. 2016

Soft Matter

View full text Add to dashboard Cite

The adsorption of single colloidal microparticles (0.5-1 µm radius) at a water-oil interface has been recently studied experimentally using digital holographic microscopy [Kaz et al., Nat. Mater., 2012, 11, 138-142]. An initially fast adsorption dynamics driven by capillary forces is followed by an unexpectedly slow relaxation to equilibrium that is logarithmic in time and can span hours or days. The slow relaxation kinetics has been attributed to the presence of surface "defects" with nanoscale dimensions (1-5 nm) that induce multiple metastable configurations of the contact line perimeter. A kinetic model considering thermally activated transitions between such metastable configurations has been proposed [Colosqui et al., Phys. Rev. Lett., 2013, 111, 028302] to predict both the relaxation rate and the crossover point to the slow logarithmic regime. However, the adsorption dynamics observed experimentally before the crossover point has remained unstudied. In this work, we propose a Langevin model that is able to describe the entire adsorption process of single colloidal particles by considering metastable states produced by surface defects and thermal motion of the particle and liquid interface. Invoking the fluctuation dissipation theorem, we introduce a drag term that considers significant dissipative forces induced by thermal fluctuations of the liquid interface. Langevin dynamics simulations based on the proposed adsorption model yield close agreement with experimental observations for different microparticles, capturing the crossover from (fast) capillary driven dynamics to (slow) thermally activated kinetics.

show abstract

Plasma Polymer Deposition: A Versatile Tool for Stem Cell Research

MacGregor

Vasilev

2016

Advanced Surfaces for Stem Cell Research

View full text Add to dashboard Cite

The influence of topography on dynamic wetting

Cited by 109 publications

References 161 publications

Crossover from shear-driven to thermally activated drainage of liquid-infused microscale capillaries

Crossover from shear-driven to thermally activated drainage of liquid-infused microscale capillaries

Colloidal particle adsorption at liquid interfaces: capillary driven dynamics and thermally activated kinetics

Plasma Polymer Deposition: A Versatile Tool for Stem Cell Research

Contact Info

Product

Resources

About