Equilibrium height of a liquid in a gap between corrugated walls under spontaneous capillary penetration

Gutiérrez, Guadalupe Juliana; Medina, A.; Higuera, F. J.

doi:10.1016/j.jcis.2009.06.056

Cited by 4 publications

(5 citation statements)

References 13 publications

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“…[8][9][10][11][12] More recently, tubes of non-circular cross sections have also been considered. 13 Of more relevance to our work are generalizations of the Lucas-Washburn solution to tubes and channels of gradually varying cross sections. Using the lubrication approximation, one-dimensional (1D) solutions have been obtained for sinusoidal tubes, 14,15 sinusoidal tubes with tortuosity 16 and tubes and channels with convergent, divergent, and power-law cross sections.…”

Section: Introductionmentioning

confidence: 99%

Wicking flow through microchannels

2011

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We report numerical simulations of wicking through micropores of two types of geometries, axisymmetric tubes with contractions and expansions of the cross section, and two-dimensional planar channels with a Y-shaped bifurcation. The aim is to gain a detailed understanding of the interfacial dynamics in these geometries, with an emphasis on the motion of the three-phase contact line. We adopt a diffuse-interface formalism and use Cahn-Hilliard diffusion to model the moving contact line. The Stokes and Cahn-Hilliard equations are solved by finite elements with adaptive meshing. The results show that the liquid meniscus undergoes complex deformation during its passage through contraction and expansion. Pinning of the interface at protruding corners limits the angle of expansion into which wicking is allowed. For sufficiently strong contractions, the interface negotiates the concave corners, thanks to its diffusive nature. Capillary competition between branches downstream of a Y-shaped bifurcation may result in arrest of wicking in the wider branch. Spatial variation of wettability in one branch may lead to flow reversal in the other.

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Section: Introductionmentioning

confidence: 99%

Wicking flow through microchannels

2011

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“…In particular, the influence of mold rising angle has been underestimated, in spite of its significant effect in the capillary action of polymer solution. [25][26][27][28][29] In this letter, we demonstrate the role of the aforementioned three experimental parameters on the formation of molded microstructures in the SAMo process aided by a good solvent. By employing and testing 24 combinations of the parameters, completely or partially molded microstructures were observed with the use of patterning and mold materials of poly(methyl methacrylate) (PMMA, M w = 120 000) in toluene and PDMS, respectively.…”

Section: Introductionmentioning

confidence: 77%

“…Accordingly, extensive studies have been made to investigate the role of experimental parameters such as permeability and absorption/evaporation kinetics. , In addition, some morphological changes in the molded microstructures with polymer concentration were also reported. , However, there has been no comprehensive study reporting on the role of various experimental conditions such as mold rising angle (defined as an angle between substrate and mold sidewall), polymer concentration, and amount of polymer solution. In particular, the influence of mold rising angle has been underestimated, in spite of its significant effect in the capillary action of polymer solution. − …”

Section: Introductionmentioning

confidence: 99%

Effects of Mold Rising Angle and Polymer Concentration in Solvent-Assisted Molding

et al. 2009

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We investigated the capillary rise of a thin polymer solution in a simple soft lithographic technique termed "solvent-assisted molding (SAMo)" by using various mold rising angles and polymer concentrations in a good solvent. For patterning and mold materials, poly(methyl methacrylate) (PMMA, M(w) = 120,000) in toluene and poly(dimethyl siloxane) (PDMS) were mostly used. It was found that the capillary rise takes place in two steps: (i) a low-viscosity polymer solution rapidly rises into the cavity (<10 s) with the aid of solvent wetting and (ii) continuous solvent absorption into the mold and evaporation into air. In addition, five distinct microstructures were observed by testing 24 different experimental combinations, which can be classified into completely molded (I), humped (II), completely molded but non-fully filled (III), partially filled (IV), and partially filled meniscal (V) microstructures.

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“…(4.3) is solved numerically by a finite-difference method on a Cartesian grid in the ng plane with N n evenly spaced divisions in the n direction and N g evenly spaced divisions in the g direction [5]. The finite-difference equation corresponding to (4…”

Section: Methodsmentioning

confidence: 99%

“…Kralchevsky, Danov, and coworkers conducted theoretical and experimental studies on the shape of the meniscus between cylinders and vertical plates and provided estimates for the associated capillary force [3]. Gutierrez et al [4] studied the meniscus developing between two narrowly-spaced corrugated plates regarded as a prototypical microchannel. In their experiments, surfaces with cylindrical protuberances having nearly semi-circular cross-sections were employed.…”

Section: Introductionmentioning

confidence: 99%