Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-26T10:41:16.544Z Has data issue: false hasContentIssue false

The spreading and stability of a surfactant-laden drop on an inclined prewetted substrate

Published online by Cambridge University Press:  07 May 2015

J. V. Goddard
Affiliation:
School of Computing and Mathematics, Keele University, Keele, Staffordshire ST5 5BG, UK
S. Naire*
Affiliation:
School of Computing and Mathematics, Keele University, Keele, Staffordshire ST5 5BG, UK
*
Email address for correspondence: [email protected]

Abstract

We consider a viscous drop, loaded with an insoluble surfactant, spreading over an inclined plane that is covered initially with a thin surfactant-free liquid film. Lubrication theory is employed to model the flow using coupled nonlinear evolution equations for the film thickness and surfactant concentration. Exploiting high-resolution numerical simulations, we describe the late-time multi-region asymptotic structure of the spatially one-dimensional spreading flow. A simplified differential–algebraic equation model is derived for key variables characterising the spreading process, using which the late-time spreading and thinning rates are determined. Focusing on the neighbourhood of the drop’s leading-edge effective contact line, we then examine the stability of this region to small-amplitude disturbances with transverse variation. A dispersion relationship is described using long-wavelength asymptotics and numerical simulations, which reveals physical mechanisms and new scaling properties of the instability.

Type
Papers
Copyright
© 2015 Cambridge University Press 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Afsar-Siddiqui, A. B., Luckham, P. F. & Matar, O. K. 2003a The spreading of surfactant solutions on thin liquid films. Adv. Colloid Interface Sci. 106, 183236.CrossRefGoogle ScholarPubMed
Afsar-Siddiqui, A. B., Luckham, P. F. & Matar, O. K. 2003b Unstable spreading of aqueous anionic surfactant solutions on liquid film. Part 1. Sparingly soluble surfactant. Langmuir 19, 696702.Google Scholar
Afsar-Siddiqui, A. B., Luckham, P. F. & Matar, O. K. 2003c Unstable spreading of aqueous anionic surfactant solutions on liquid films. Part 2. Highly soluble surfactant. Langmuir 19, 703708.Google Scholar
Afsar-Siddiqui, A. B., Luckham, P. F. & Matar, O. K. 2004 Dewetting behavior of aqueous cationic surfactant solutions on liquid films. Langmuir 20, 75757582.Google Scholar
Bertozzi, A. L. & Brenner, M. P. 1997 Linear stability and transient growth in driven contact lines. Phys. Fluids 9 (3), 530539.Google Scholar
Craster, R. V. & Matar, O. K. 2009 Dynamics and stability of thin liquid films. Rev. Mod. Phys. 81, 11311198.Google Scholar
Dussan, E. B. & Davis, S. 1974 On the motion of a fluid–fluid interface along a solid surface. J. Fluid Mech. 65, 7195.Google Scholar
Edmonstone, B. D., Matar, O. K. & Craster, R. V. 2004 Flow of surfactant-laden thin films down an inclined plane. J. Engng Maths 50, 141156.Google Scholar
Edmonstone, B. D., Matar, O. K. & Craster, R. V. 2005a Coating of an inclined plane in the presence of insoluble surfactant. J. Colloid Interface Sci. 287, 261272.Google Scholar
Edmonstone, B. D., Matar, O. K. & Craster, R. V. 2005b Surfactant-induced fingering phenomena in thin film flow down an inclined plane. Physica D 209, 6279.Google Scholar
Edmonstone, B. D., Matar, O. K. & Craster, R. V. 2006 A note on the coating of an inclined plane in the presence of soluble surfactant. J. Colloid Sci. 293, 222229.Google Scholar
Eres, M. H., Schwartz, L. W. & Roy, R. V. 2000 Fingering phenomena for driven coating films. Phys. Fluids 12, 12781295.Google Scholar
Grotberg, J. B. 1994 Pulmonary flow and transport phenomena. Annu. Rev. Fluid Mech. 26, 529571.Google Scholar
Grotberg, J. B. 2001 Respiratory fluid mechanics and transport processes. Annu. Rev. Biomed. Engng 3, 421457.Google Scholar
Hocking, L. M. 1990 Spreading and instability of a viscous fluid sheet. J. Fluid Mech. 211, 373392.Google Scholar
Hocking, L. M., Debler, W. R. & Cook, K. E. 1999 The growth of leading-edge distortions on a viscous sheet. Phys. Fluids 11 (2), 307313.Google Scholar
Homsy, G. M. 1987 Viscous fingering in porous media. Annu. Rev. Fluid Mech. 19, 271311.Google Scholar
Huh, C. & Scriven, L. E. 1971 Hydrodynamical model of steady movement of a solid/liquid/fluid contact line. J. Colloid Interface Sci. 35, 85101.CrossRefGoogle Scholar
Huppert, H. E. 1982 The flow and instability of viscous gravity currents down a slope. Nature 300, 427429.Google Scholar
Jensen, O. 1994 Self-similar, surfactant driven flows. Phys. Fluids A 6, 10841094.CrossRefGoogle Scholar
Jensen, O. E. & Grotberg, J. B. 1992 Insoluble surfactant spreading on a thin viscous film: shock evolution and film rupture. J. Fluid Mech. 240, 259288.CrossRefGoogle Scholar
Jensen, O. E. & Halpern, D. 1998 The stress singularity in surfactant-driven thin-film flows. Part 1. Viscous elements. J. Fluid Mech. 372, 273300.CrossRefGoogle Scholar
Jensen, O. E. & Naire, S. 2006 The spreading and stability of a surfactant-laden drop on a prewetted substrate. J. Fluid Mech. 554, 524.Google Scholar
Jerrett, J. M. & de Bruyn, J. R. 1992 Fingering instability of a gravitationally driven contact line. Phys. Fluids A 4 (2), 234242.CrossRefGoogle Scholar
Kondic, L. E. & Diez, J. A. 2001 Pattern formation in the flow of thin films down an incline: constant flux configuration. Phys. Fluids 13 (11), 31643184.Google Scholar
Kondic, L. E. & Diez, J. A. 2002 Computing three-dimensional thin film flows using contact lines. J. Comput. Phys. 183, 274306.Google Scholar
Levy, R. & Shearer, M. 2006 The motion of a thin film driven by surfactant and gravity. SIAM J. Appl. Maths 66, 15881609.Google Scholar
Levy, R., Shearer, M. & Witelski, T. P. 2007 Gravity-driven thin liquid films with insoluble surfactant: smooth travelling waves. Eur. J. Appl. Maths 8 (6), 679708.Google Scholar
Marmur, A. & Lelah, M. D. 1981 The spreading of aqueous surfactant solutions on glass. Chem. Engng Commun. 13, 133143.Google Scholar
Matar, O. K. & Craster, R. V. 2009 Dynamics of surfactant-assisted spreading. Soft Matt. 5, 38013809.Google Scholar
Mavromoustaki, A.2011 Long-wave dynamics of single- and two-layer flows. PhD thesis, Imperial College of Science, Technology and Medicine, London.Google Scholar
Mavromoustaki, A., Matar, O. K. & Craster, R. V. 2012a Dynamics of a climbing surfactant-laden film – I: base-state flow. J. Colloid Interface Sci. 371, 107120.Google Scholar
Mavromoustaki, A., Matar, O. K. & Craster, R. V. 2012b Dynamics of a climbing surfactant-laden film – II: stability. J. Colloid Interface Sci. 371, 121135.CrossRefGoogle ScholarPubMed
Rosen, M. J. 2004 Surfactants and Interfacial Phenomena, 3rd edn. Wiley.Google Scholar
Schwartz, L. W. 1989 Viscous flows down an inclined plane: instability and finger formation. Phys. Fluids A 1, 443445.Google Scholar
Silvi, N. & Dussan, E. B. 1985 On the rewetting of an inclined solid surface by a liquid. Phys. Fluids 28 (1), 57.CrossRefGoogle Scholar
Spaid, M. A. & Homsy, G. M. 1996 Stability of Newtonian and viscoelastic dynamic contact lines. Phys. Fluids 8, 460478.Google Scholar
Troian, S. M., Herbolzheimer, E. & Safran, S. A. 1990 Model for the fingering instability of the spreading surfactant drops. Phys. Rev. Lett. 65, 333336.CrossRefGoogle ScholarPubMed
Troian, S. M., Herbolzheimer, E., Safran, S. A. & Joanny, J. F. 1989 Fingering instabilities of driven spreading films. Europhys. Lett. 10 (1), 2530.Google Scholar
Warner, M. R. E., Craster, R. V. & Matar, O. K. 2004 Fingering phenomena associated with insoluble surfactant spreading on thin liquid films. J. Fluid Mech. 510, 169200.CrossRefGoogle Scholar