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Roughening transition in a moving contact line
Ramin Golestanian1, Elie Raphaël
1Laboratoire de Physique de la Matière Condensée, College de France, UMR 7125 et FR 2438 du CNRS, 11 Place Marcelin-Berthelot, 75231 Paris Cedex 05, France.
Summary
This study unifies coating and pinning transitions for moving contact lines on disordered surfaces as roughening transitions. A phase diagram reveals how disorder influences these dynamics, impacting film formation.
Area of Science:
- Physics of soft matter
- Fluid dynamics
- Surface science
Background:
- Moving contact lines on disordered substrates exhibit complex behaviors like coating and pinning.
- Understanding these dynamics is crucial for applications in coatings, printing, and microfluidics.
Purpose of the Study:
- To formulate the dynamics of moving contact lines on disordered substrates.
- To unify the understanding of coating and pinning transitions within a single theoretical framework.
- To propose a phase diagram characterizing these transitions.
Main Methods:
- Formulation of contact line dynamics considering local and hydrodynamic dissipation.
- Analysis of coating transitions at high velocities and pinning transitions at low velocities.
- Development of a unified framework based on roughening transitions.
Main Results:
- Both coating and pinning transitions are identified as roughening transitions of the contact line.
- A phase diagram is proposed where coating and pinning transition boundaries meet.
- Strong disorder leads to immediate Landau-Levich film formation after depinning.
Conclusions:
- The study provides a unified framework for understanding contact line dynamics on disordered surfaces.
- The proposed phase diagram offers insights into the influence of disorder strength and velocity.
- The findings have implications for controlling fluid behavior and film formation in various applications.