A numerical study of nanoscale electrohydrodynamic patterning in a liquid film

Yang, Qingzhen; Li, Ben Q.; Ding, Yucheng

doi:10.1039/c3sm27239g

Cited by 29 publications

(25 citation statements)

References 29 publications

(70 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the given set of parameters and assuming that the dimensionless wavelength of the initial disturbance is approximately equal to s þ w, we get Ca cr ¼ 40:89. It appears that linear theory significantly over-predicts the critical voltage and this was also found to be true in the non-linear simulations presented by [30]. The loss of interfacial periodicity that is observed in the evolution of the metastable equilibrium appears to be a more general characteristic of the present problem.…”

Section: Newtonian Fluidsupporting

confidence: 63%

“…4b) and we find that for the given set of parameters it is approximately equal to Ca % 10. According to linear theory [9,30] the critical Ca can be evaluated using the following expression…”

Section: Newtonian Fluidmentioning

confidence: 99%

“…Examples of fully non-linear simulations without making use of the lubrication approximation are the works of [28][29][30][31] who studied primarily cases involving heterogeneous electric fields. Yang et al [30], motivated by the work of Heier et al [9], considered a sinusoidally patterned top electrode and performed non-linear simulations using a boundary/finite element method to determine the critical parameters for instability of the liquid film. Their results indicate that linear analysis can significantly over-predict the critical voltage for instability.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Non-linear dynamics of a viscoelastic film subjected to a spatially periodic electric field

Karapetsas¹,

Bontozoglou²

2015

Journal of Non-Newtonian Fluid Mechanics

View full text Add to dashboard Cite

We investigate the non-linear dynamics of the electrohydrodynamic instability of a viscoelastic polymeric film under a patterned mask. We develop a computational model and carry out 2D numerical simulations fully accounting for the flow and electric field in both phases. We perform a thorough parametric study and investigate the influence of the various rheological parameters, the applied voltage and the period of the protrusions of the mask in order to define the fabrication limits of this process in the case of patterned electrodes. Our results indicate that the effect of elasticity is destabilizing, in agreement with earlier studies in the literature based on linear stability analysis for homogeneous electric fields. However, the significance of the normal and shear polymeric stress components is found to change drastically as deformation advances, rendering inappropriate the lubrication approximation that neglects normal stresses. We also find that for low values of the Ca number a metastable state arises with finite interfacial deformation, the amplitude of which compares favourably with experimental observations in contrast with earlier predictions using linear theory. Though the critical voltage for this metastable state appears to be unaffected by the elasticity of the material, viscoelasticity affects the fabrication limit on the period of the protrusions of the top electrode

show abstract

Section: Newtonian Fluidsupporting

confidence: 63%

Section: Newtonian Fluidmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Non-linear dynamics of a viscoelastic film subjected to a spatially periodic electric field

Karapetsas¹,

Bontozoglou²

2015

Journal of Non-Newtonian Fluid Mechanics

View full text Add to dashboard Cite

show abstract

“…Different numerical methods are used to track the free interfaces [20,21], and particularly, in the EHD patterning process [22][23][24][25]. The numerical methods are applied as versatile tools to monitor and visualize the transient evolution of liquid film subject to an electric field.…”

Section: Numerical Schemementioning

confidence: 99%

Electrified Pressure-Driven Instability in Thin Liquid Films

Nazaripoor¹,

Riad²,

Sadrzadeh³

2018

Electric Field

View full text Add to dashboard Cite

The electrified pressure-driven instability of thin liquid films, also called electrohydrodynamic (EHD) lithography, is a pattern transfer method, which has gained much attention due to its ability in the fast and inexpensive creation of novel micro-and nanosized features. In this chapter, the mathematical model describing the dynamics and spatiotemporal evolution of thin liquid film is presented. The governing hydrodynamic equations, intermolecular interactions, and electrostatic force applied to the film interface and assumptions used to derive the thin film equation are discussed. The electrostatic conjoining/disjoining pressure is derived based on the long-wave limit approximation since the film thickness is much smaller than the characteristic wavelength for the growth of instabilities. An electrostatic model, called an ionic liquid (IL) model, is developed which considers a finite diffuse electric layer with a comparable thickness to the film. This model overcomes the lack of assuming very large and small electrical diffuse layer, as essential elements in the perfect dielectric (PD) and the leaky dielectric (LD) models, respectively. The ion distribution within the IL film is considered using the Poisson-Nernst-Planck (PNP) model. The resulting patterns formed on the film for three cases of PD-PD, PD-IL, and IL-PD double layer system are presented and compared.

show abstract

“…Electrohydrodynamic (EHD) destabilization of molten polymer or liquid films has received extensive attention over the past few decades as a unique and interesting approach for creating micron-and submicron-sized features for soft lithography [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and coatings. 17,18 In this process, a thin liquid film is sandwiched between two electrodes and an electric field is applied to the film in the transverse direction (see Fig.…”

Section: Introductionmentioning

confidence: 99%

Compact micro/nano electrohydrodynamic patterning: using a thin conductive film and a patterned template

et al. 2016

View full text Add to dashboard Cite

The influence of electrostatic heterogeneity on the electric-field-induced destabilization of thin ionic liquid (IL) films is investigated to control spatial ordering and to reduce the lateral dimension of structures forming on the films. Commonly used perfect dielectric (PD) films are replaced with ionic conductive films to reduce the lateral length scales to a sub-micron level in the EHD pattering process. The 3-D spatiotemporal evolution of a thin IL film interface under homogenous and heterogeneous electric fields is numerically simulated. Finite differences in the spatial directions using an adaptive time step ODE solver are used to solve the 2-D nonlinear thin film equation. The validity of our simulation technique is determined from close agreement between the simulation results of a PD film and the experimental results in the literature. Replacing the flat electrode with the patterned one is found to result in more compact and well-ordered structures particularly when an electrode with square block protrusions is used. This is attributed to better control of the characteristic spatial lengths by applying a heterogeneous electric field by patterned electrodes. The structure size in PD films is reduced by a factor of 4 when they are replaced with IL films, which results in nano-sized features with well-ordered patterns over the domain.

show abstract

A numerical study of nanoscale electrohydrodynamic patterning in a liquid film

Cited by 29 publications

References 29 publications

Non-linear dynamics of a viscoelastic film subjected to a spatially periodic electric field

Non-linear dynamics of a viscoelastic film subjected to a spatially periodic electric field

Electrified Pressure-Driven Instability in Thin Liquid Films

Compact micro/nano electrohydrodynamic patterning: using a thin conductive film and a patterned template

Contact Info

Product

Resources

About