Dynamic Wetting Processes: Modelling and Simulation

1. Dynamic Wetting Processes:Modelling and Simulation J.E. Sprittles (University of Birmingham / Oxford, U.K.) Y.D. Shikhmurzaev (University of Birmingham, U.K.) Seminar at KAUST, February 2012

2. ‘Impact’ A few years after completing my PhD.....

3. Wetting: Statics Wettable (Hydrophilic) Non-Wettable (Hydrophobic)

4. Wetting: Dynamics

5. Wetting: As a Microscopic Process Wetting front Microscale Macroscale Capillary tube Meniscus

6. Wetting: Micro-Macro Spreading on a Porous Medium

7. Processes with Wetting at their Core

8. Capillary Rise 27mm Radius Tube Stangeet al 03 50nm x 900nm Channels Han et al 06 1 Million Orders of Magnitude!!

9. Curtain Coating

10. Curtain Coating Optimization Increased Coating Speed

11. Harnessing Instabilities: Spinning Disk Atomizer

12. Polymer-Organic LED (P-OLED) Displays

13. Inkjet Printing of P-OLED Displays Microdrop Impact & Spreading

14. Additive Manufacturing

15. Modelling

16. Why bother? • - Recover Hidden Information • - Map Regimes of Spreading 3 – Experiment Millimetres in Milliseconds - Riobooet al (2002) Microns in Microseconds - Dong et al (2002)

17. Wetting: Statics ) Contact Line Contact Angle Laplace Young

18. Wetting: Statics

19. Dynamics: Classical Modelling ) Incompressible Navier Stokes Stress balance Kinematic condition No Solution! No-Slip Impermeability Angle Prescribed

20. ‘Moving Contact Line Problem’ L.E.Scriven (1971), C.Huh (1971), A.W.Neumann (1971), S.H. Davis (1974), E.B.Dussan (1974), E.Ruckenstein (1974), A.M.Schwartz (1975), M.N.Esmail (1975), L.M.Hocking (1976), O.V.Voinov (1976), C.A.Miller (1976), P.Neogi (1976), S.G.Mason (1977), H.P.Greenspan (1978), F.Y.Kafka (1979), L.Tanner (1979), J.Lowndes (1980), D.J. Benney (1980), W.J.Timson (1980), C.G.Ngan (1982), G.F.Telezke (1982), L.M.Pismen (1982), A.Nir (1982), V.V.Pukhnachev (1982), V.A.Solonnikov (1982), P.-G. de Gennes (1983), V.M.Starov (1983), P.Bach (1985), O.Hassager (1985), K.M.Jansons (1985), R.G.Cox (1986), R.Léger (1986), D.Kröner (1987), J.-F.Joanny (1987), J.N.Tilton (1988), P.A.Durbin (1989), C.Baiocchi (1990), P.Sheng (1990), M.Zhou (1990), W.Boender (1991), A.K.Chesters (1991), A.J.J. van derZanden (1991), P.J.Haley (1991), M.J.Miksis (1991), D.Li (1991), J.C.Slattery (1991), G.M.Homsy (1991), P.Ehrhard (1991), Y.D.Shikhmurzaev (1991), F.Brochard-Wyart (1992), M.P.Brenner (1993), A.Bertozzi (1993), D.Anderson (1993), R.A.Hayes (1993), L.W.Schwartz (1994), H.-C.Chang (1994), J.R.A.Pearson (1995), M.K.Smith (1995), R.J.Braun (1995), D.Finlow (1996), A.Bose (1996), S.G.Bankoff (1996), I.B.Bazhlekov (1996), P.Seppecher (1996), E.Ramé (1997), R.Chebbi (1997), R.Schunk (1999), N.G.Hadjconstantinou (1999), H.Gouin (10999), Y.Pomeau (1999), P.Bourgin (1999), M.C.T.Wilson (2000), D.Jacqmin (2000), J.A.Diez (2001), M.&Y.Renardy (2001), L.Kondic (2001), L.W.Fan (2001), Y.X.Gao (2001), R.Golestanian (2001), E.Raphael (2001), A.O’Rear (2002), K.B.Glasner (2003), X.D.Wang (2003), J.Eggers (2004), V.S.Ajaev (2005), C.A.Phan (2005), P.D.M.Spelt (2005), J.Monnier (2006)

21. Dynamic Contact Angle • Required as a boundary condition for the free surface shape. r r t Pasandideh-Fard et al 1996

22. ) U Speed-Angle Formulae Dynamic Contact Angle Formula Young Equation σ1 σ3 - σ2 Assumption: A unique angle for each speed R

23. Capillary Rise Experiments

24. The Interface Formation Model

25. Physics of Dynamic Wetting Liquid-solid interface Solid Forming interface Formed interface • Make a dry solid wet. • Create a new/fresh liquid-solid interface. • Class of flows with forming interfaces.

26. Relevance of the Young Equation Static situation Dynamic wetting σ1e σ1 θe θd σ3 - σ2 σ3e - σ2e R R Dynamic contact angle results from dynamic surface tensions. Theangle is now determined by the flow field. Slip created by surface tension gradients (Marangoni effect)

27. f (r, t )=0 e1 n n θd e2 Interface Formation Modelling In the bulk: Interface Formation Model On free surfaces: On liquid-solid interfaces: At contact lines:

28. Comparison With Experiments Perfect wetting(Hoffman 1975; Ström et al. 1990; Fermigier & Jenffer 1991) Partial wetting(□: Hoffman 1975; : Burley & Kennedy 1976; , , : Ström et al. 1990) The theory is in good agreement with all experimental data published in the literature.

29. A Computational Framework

30. Graded Mesh – For Both Models

31. Arbitrary Lagrangian-Eulerian(Free surface nodes follow the fluid’s path; bulk’s don’t)

32. Oscillating Drops: Code Validation For Re=100, f2 = 0.9

33. Oscillating Drops: Code Validation a b

34. Drop Impact

35. Impact at Different Scales Millimetre Drop Microdrop Nanodrop

36. Pyramidal (mm-sized) Drops Experiment Renardy et al.

37. Microdrop Impact

38. Microdrop Impact and Spreading Pressure Scale Velocity Scale

39. Typical Microdrop Experiment (Dong et al 07) ? ?

40. Recovering Hidden Information

41. Flow Over Surfaces of Variable Wettability

42. Periodically Patterned Surfaces • No slip – No effect.

43. Interface Formation vs Molecular Dynamics Solid 2 less wettable Qualitative agreement

44. Surfaces of Variable Wettability 1 1.5

45. Flow Control on Patterned Surfaces

46. Capillary Rise

47. Capillary Rise

48. Flow Characteristics

49. ‘Hydrodynamic Resist’