Pattern formation in thin liquid films with charged surfactants

Warner, M. R. E.; Matar, Omar

doi:10.1016/j.jcis.2003.08.013

Cited by 18 publications

(17 citation statements)

References 39 publications

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“…Short-range repulsion avoiding the contactline singularity arises not only from the orbital overlaps, but, in some cases, also due to specific factors such as van der Waals with a thin wettable top coating of the substrate, entropic effects in absorbed or grafted polymer films, hydrophilic repulsion, etc. [29][30][31]. The set of parameters used for the simulations are A ff = 5.79 × 10 −20 J, A ss = 2.5 × 10 −20 J, l 0 = 7 nm, μ = 1 Pa s, and γ f = 30.8 mJ/m 2 .…”

Section: Methodsmentioning

confidence: 99%

“…The problem of universal pathways of dewetting and the resulting microstructures on a solid substrate have been addressed extensively, both theoretically [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] and experimentally [40][41][42][43][44][45][46][47]. The excess intermolecular interactions on a uniform substrate produce rather disordered patterns, although with a well-defined mean length scale.…”

Section: Introductionmentioning

confidence: 99%

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Spinodal instability and pattern formation in thin liquid films confined between two plates

Verma

Sharma

Banerjee

et al. 2006

Journal of Colloid and Interface Science

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spinodal instability and pattern formation in thin liquid films confined between two plates

Verma

Sharma

Banerjee

et al. 2006

Journal of Colloid and Interface Science

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“…14 Related recent applications have included utilizing an electrokinetic instability as a micromixer 15 or considering how electrical charges could be utilized with surfactants to create patterning. 16 A review by Saville 17 summarizes the effect of electric fields in engendering electrohydrodynamic instabilities in systems featuring fluid-fluid interfaces. The majority of the work described therein involves situations where gravity is important and a critical voltage is required to destabilize disturbances of intermediate wavenumber; long and short wavelength disturbances are stabilized by gravity and capillarity, respectively.…”

Section: Introductionmentioning

confidence: 99%

Electrically induced pattern formation in thin leaky dielectric films

Matar

2005

Physics of Fluids

127

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The stability of the interface between two thin leaky dielectric liquid layers bounded between two flat electrodes is considered. A coupled system of evolution equations is derived for the interfacial location and charge density using lubrication theory. This system is parametrized by the dielectric constants of the two fluids in addition to ratios of their conductivities, viscosities, and thicknesses. A linear stability analysis is conducted and the behavior of the system in the nonlinear regime is also examined. The system is destabilized by electrical stresses that are resisted by capillarity and modified by viscous dissipation. Our results suggest that decreasing the thickness ratio is destabilizing, giving rise to periodic structures of decreasing wavelength. Decreasing the viscosity ratio was also found to lead to the formation of sharp-edged structures whose vertical extent is virtually equal to the gap width between the electrodes. Similar structures were also determined upon increasing the ratio of the dielectric constants and electric conductivities.

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] In many of the coating applications, homogeneity, uniformity, and durability of the thin films are essential, [3][4][5][6][7] but in soft lithography-based patterning applications, the film instability needs to be controlled and guided for engineering of self-organized mesostructures. [9][10][11][12][13][14][15][16][17][18][19] As films become thinner, they become increasingly susceptible to defects resulting from the coating process, conjoining pressure, [20][21][22][23][24][25][26][27][28][29][30][31][32] or substrate nonuniformities. …”

Section: Introductionmentioning

confidence: 99%

Defect Sensitivity in Instability and Dewetting of Thin Liquid Films: Two Regimes of Spinodal Dewetting

Verma

Sharma

2006

Ind. Eng. Chem. Res.

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The instability, dynamics, and dewetting engendered by the van der Waals forces in a thin liquid film sandwiched between a solid substrate and bulk fluid phase are investigated based on linear stability analysis and large-area, nonlinear 2D and 3D simulations. The effects of initial free-surface heterogeneities on the length scale of instability, morphology, order of the resulting structures, and their dynamic evolution are examined. The simulations clearly show two distinct regimes of spinodal instability: (a) deep inside the spinodal territory (DIST) and (b) a defect-sensitive spinodal regime (DSSR). The latter regime with increased sensitivity to the initial conditions and local ordering and clustering of holes is obtained toward the periphery of the spinodal region where spinodal destabilization becomes weak, or the force per unit volume ∂φ/∂h f 0. Thus, relatively thin and thick films close to the spinodal boundaries that do rupture by the spinodal mechanism may give the appearance of nucleation-induced rupture. Finally, the effects of simulation domain size (or number of holes) on the morphological and dynamic characteristics of spinodal instability are studied to assess the minimal sample size of simulations required to faithfully mirror some important aspects of thin-film rupture.

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Pattern formation in thin liquid films with charged surfactants

Cited by 18 publications

References 39 publications

Spinodal instability and pattern formation in thin liquid films confined between two plates

Spinodal instability and pattern formation in thin liquid films confined between two plates

Electrically induced pattern formation in thin leaky dielectric films

Defect Sensitivity in Instability and Dewetting of Thin Liquid Films: Two Regimes of Spinodal Dewetting

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