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63 rd Annual DFD Meeting of the American Physical Society Long Beach, California

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63 rd Annual DFD Meeting of the American Physical Society Long Beach, California

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  1. 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

  2. Motivation • Contact line dynamics • Rapidly growing fields of: • Microfluidics • Miniaturisation of chemical devices • Small lengthscale  solid surface propertiesbecome crucial

  3. 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

  4. Modelling • Phase field approach • f represents the 2 phases • Interface at f=0

  5. 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

  6. 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

  7. Modelling • Wetting boundary condition • Conserved dynamic equation Standard deviation s = disorder strength [1] with [1]Cahn, J. Chem. Phys. 66 (1977), 3667

  8. Results and discussion • 2D configuration • Typical simulation result

  9. Results and discussion • 2D configuration • Typical simulation result • Statisticalanalysis on severaldisorderrealisations

  10. Results and discussion • 2D configuration • Typical simulation result • Statistical analysis on several disorder realisations

  11. Results and discussion • 2D configuration • Typical simulation result • Statistical analysis on several disorder realisations

  12. Results and discussion • 2D configuration • Typical simulation result • Statistical analysis on several disorder realisations

  13. Results and discussion • 2D configuration • Typical simulation result • Statistical analysis on several disorder realisations Chemical disorder  contact angle hysteresis enhanced by disorder strength

  14. Results and discussion • 3D configuration • Contact line dynamics: preliminaryanalysis • interface widthfollows fractal dynamics ( scale-invariant growth)

  15. 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

  16. 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

  17. 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

  18. Modelling • Boundary conditions for 2D configuration

  19. Modelling • Boundary conditions for 3D configuration

  20. Results and discussion • 2D configuration • Typical simulation result • Statistical analysis on several disorder realisations Chemical disorder  contact angle hysteresis enhanced by disorder strength

  21. Results and discussion • 3D configuration • Typical simulation results

  22. Results and discussion • 3D configuration • Typical simulation results • Contact line dynamic: preliminary analysis • interface width growth follows fractal dynamic

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