Thin films in partial wetting: internal selection of contact-line dynamics
When a liquid touches a solid surface, it spreads to minimize the system's energy. The classic thin-film model describes the spreading as an interplay between gravity, capillarity and viscous forces, but cannot see an end to this process as it does not account for the nonhydrodynamic liquid--so...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | en_US |
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American Physical Society
2015
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| Online Access: | http://hdl.handle.net/1721.1/97738 https://orcid.org/0000-0002-7370-2332 https://orcid.org/0000-0003-3505-9718 https://orcid.org/0000-0001-8323-2779 https://orcid.org/0000-0003-3958-7382 |
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| author | Alizadeh Pahlavan, Amir Cueto-Felgueroso, Luis McKinley, Gareth H. Juanes, Ruben |
| author2 | Massachusetts Institute of Technology. Department of Civil and Environmental Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Civil and Environmental Engineering Alizadeh Pahlavan, Amir Cueto-Felgueroso, Luis McKinley, Gareth H. Juanes, Ruben |
| author_sort | Alizadeh Pahlavan, Amir |
| collection | MIT |
| description | When a liquid touches a solid surface, it spreads to minimize the system's energy. The classic thin-film model describes the spreading as an interplay between gravity, capillarity and viscous forces, but cannot see an end to this process as it does not account for the nonhydrodynamic liquid--solid interactions. While these interactions are important only close to the contact line, where the liquid, solid and gas meet, they have macroscopic implications: in the partial-wetting regime, a liquid puddle ultimately stops spreading. We show that by incorporating these intermolecular interactions, the free energy of the system at equilibrium can be cast in a Cahn--Hilliard framework with a height-dependent interfacial tension. Using this free energy, we derive a mesoscopic thin-film model that describes statics and dynamics of liquid spreading in the partial-wetting regime. The height-dependence of the interfacial tension introduces a localized apparent slip in the contact-line region and leads to compactly-supported spreading states. In our model, the contact line dynamics emerge naturally as part of the solution and are therefore nonlocally coupled to the bulk flow. Surprisingly, we find that even in the gravity-dominated regime, the dynamic contact angle follows the Cox--Voinov law. |
| first_indexed | 2024-09-23T14:49:04Z |
| format | Article |
| id | mit-1721.1/97738 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T14:49:04Z |
| publishDate | 2015 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/977382022-09-29T10:44:19Z Thin films in partial wetting: internal selection of contact-line dynamics Alizadeh Pahlavan, Amir Cueto-Felgueroso, Luis McKinley, Gareth H. Juanes, Ruben Massachusetts Institute of Technology. Department of Civil and Environmental Engineering Massachusetts Institute of Technology. Department of Mechanical Engineering Alizadeh Pahlavan, Amir Cueto-Felgueroso, Luis McKinley, Gareth H. Juanes, Ruben When a liquid touches a solid surface, it spreads to minimize the system's energy. The classic thin-film model describes the spreading as an interplay between gravity, capillarity and viscous forces, but cannot see an end to this process as it does not account for the nonhydrodynamic liquid--solid interactions. While these interactions are important only close to the contact line, where the liquid, solid and gas meet, they have macroscopic implications: in the partial-wetting regime, a liquid puddle ultimately stops spreading. We show that by incorporating these intermolecular interactions, the free energy of the system at equilibrium can be cast in a Cahn--Hilliard framework with a height-dependent interfacial tension. Using this free energy, we derive a mesoscopic thin-film model that describes statics and dynamics of liquid spreading in the partial-wetting regime. The height-dependence of the interfacial tension introduces a localized apparent slip in the contact-line region and leads to compactly-supported spreading states. In our model, the contact line dynamics emerge naturally as part of the solution and are therefore nonlocally coupled to the bulk flow. Surprisingly, we find that even in the gravity-dominated regime, the dynamic contact angle follows the Cox--Voinov law. United States. Dept. of Energy (CAREER Award Grant DE-SC0003907) United States. Dept. of Energy. Mathematical Multifaceted Integrated Capability Center (Grant DE-SC0009286) 2015-07-15T12:47:44Z 2015-07-15T12:47:44Z 2015-07-15 2015-06 Article http://purl.org/eprint/type/JournalArticle 0031-9007 1079-7114 http://hdl.handle.net/1721.1/97738 Alizadeh Pahlavan, Amir, Luis Cueto-Felgueroso, Gareth H. McKinley, and Ruben Juanes. "Thin films in partial wetting: internal selection of contact-line dynamics." Forthcoming in Physical Review Letters. https://orcid.org/0000-0002-7370-2332 https://orcid.org/0000-0003-3505-9718 https://orcid.org/0000-0001-8323-2779 https://orcid.org/0000-0003-3958-7382 en_US http://journals.aps.org/prl/accepted/18079Y1aO511194cd818964075d4bced72a095c9f Physical Review Letters Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf American Physical Society MIT web domain |
| spellingShingle | Alizadeh Pahlavan, Amir Cueto-Felgueroso, Luis McKinley, Gareth H. Juanes, Ruben Thin films in partial wetting: internal selection of contact-line dynamics |
| title | Thin films in partial wetting: internal selection of contact-line dynamics |
| title_full | Thin films in partial wetting: internal selection of contact-line dynamics |
| title_fullStr | Thin films in partial wetting: internal selection of contact-line dynamics |
| title_full_unstemmed | Thin films in partial wetting: internal selection of contact-line dynamics |
| title_short | Thin films in partial wetting: internal selection of contact-line dynamics |
| title_sort | thin films in partial wetting internal selection of contact line dynamics |
| url | http://hdl.handle.net/1721.1/97738 https://orcid.org/0000-0002-7370-2332 https://orcid.org/0000-0003-3505-9718 https://orcid.org/0000-0001-8323-2779 https://orcid.org/0000-0003-3958-7382 |
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