63 rd annual dfd meeting of the american physical society long beach california november 21 23 2010
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63 rd annual dfd meeting of the american physical society long beach california november 21 23 2010

Contact line dynamics of a liquid meniscus advancinginto a microchannel with chemical heterogeneitiesC. Wylock1, M. Pradas2, B. Haut1, P. Colinet1 and S. Kalliadasis21Université Libre de Bruxelles – Transfers, Interfaces and Processes2Imperial College London – Chemical Engineering Department

63rd Annual DFD Meeting

of the American Physical Society

Long Beach, California

November 21-23, 2010


Motivation
Motivation

  • Contact line dynamics

    • Rapidly growing fields of:

      • Microfluidics

      • Miniaturisation of chemical devices

    • Small lengthscale

       solid surface propertiesbecome crucial


63 rd annual dfd meeting of the american physical society long beach california
Goal

  • Gas-liquidmeniscusmoving in a "Hele-Shaw celllike " microchannel

  • Surface chemicallyheterogeneous spatial distribution of wettingproperties

  • 2 configurations

  • Effect of chemicalheterogeneities on meniscusdynamics ?

2D configuration

3D configuration


Modelling
Modelling

  • Phase field approach

    • f represents the 2 phases

    • Interface at f=0


Modelling1
Modelling

  • Phase field approach

    • f represents the 2 phases

    • Interface at f=0

  • Equilibrium given by Ginzburg-Landau model

Free energy formulation

Double-well potential

Chemical potential


Modelling2
Modelling

  • Phase field approach

    • f represents the 2 phases

    • Interface at f=0

  • Equilibrium given by Ginzburg-Landau model

Free energy formulation

Double-well potential

Chemical potential


Modelling3
Modelling

  • Wetting boundary condition

  • Conserved dynamic equation

Standard deviation s

= disorder strength

[1]

with

[1]Cahn, J. Chem. Phys. 66 (1977), 3667


Results and discussion
Results and discussion

  • 2D configuration

    • Typical simulation result


Results and discussion1
Results and discussion

  • 2D configuration

    • Typical simulation result

    • Statisticalanalysis on severaldisorderrealisations


Results and discussion2
Results and discussion

  • 2D configuration

    • Typical simulation result

    • Statistical analysis on several disorder realisations


Results and discussion3
Results and discussion

  • 2D configuration

    • Typical simulation result

    • Statistical analysis on several disorder realisations


Results and discussion4
Results and discussion

  • 2D configuration

    • Typical simulation result

    • Statistical analysis on several disorder realisations


Results and discussion5
Results and discussion

  • 2D configuration

    • Typical simulation result

    • Statistical analysis on several disorder realisations

Chemical disorder  contact angle hysteresis enhanced by disorder strength


Results and discussion6
Results and discussion

  • 3D configuration

    • Contact line dynamics: preliminaryanalysis

      • interface widthfollows fractal dynamics

        ( scale-invariant growth)


Results and discussion7
Results and discussion

  • 3D configuration

    • Contact line dynamics: preliminaryanalysis

      • interface widthfollows fractal dynamics

        ( scale-invariant growth)

      • pinning-depinningeffects and associated avalanche dynamics

Pinning site

Avalanche site


Results and discussion8
Results and discussion

  • 3D configuration

    • Contact line dynamics: preliminaryanalysis

      • interface widthfollows fractal dynamics

        ( scale-invariant growth)

      • pinning-depinningeffects and associated avalanche dynamics

        induced by the chemicaldisorder

         Statisticalanalysis to perform for variousdisorder configurations


Conclusion and future plans
Conclusion and future plans

  • Phase field  contact line dynamics in chemically heterogeneous microchannel

  • Chemical disorder induces

    • 2D: hysteresis of contact angle

       hysteresis “jump” function of disorder strength

    • 3D: kinetic roughening process of contact line motion, pinning-depinning effects

  • Future plans

    • Statistical analysis for 3D configuration:

      • Characterization of the scaling growth factors

      • Avalanche dynamics


Modelling4
Modelling

  • Boundary conditions for 2D configuration


Modelling5
Modelling

  • Boundary conditions for 3D configuration


Results and discussion9
Results and discussion

  • 2D configuration

    • Typical simulation result

    • Statistical analysis on several disorder realisations

Chemical disorder  contact angle hysteresis enhanced by disorder strength


Results and discussion10
Results and discussion

  • 3D configuration

    • Typical simulation results


Results and discussion11
Results and discussion

  • 3D configuration

    • Typical simulation results

    • Contact line dynamic: preliminary analysis

      • interface width growth follows fractal dynamic