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Breakup of Thin Liquid Films: From Stochastic to Deterministic
Emmanouil Chatzigiannakis1, Jan Vermant1
1Department of Materials, ETH Zürich, Vladimir Prelog Weg 5, 8032 Zürich, Switzerland.
Physical Review Letters
|October 23, 2020
Summary
Understanding liquid film rupture is key for product stability. This study shows how hydrodynamic forces influence film breakup, shifting it from random to predictable as flow strength increases.
Area of Science:
- Fluid dynamics
- Surface science
- Polymer physics
Background:
- Thin liquid film rupture governs the stability of bubbles, droplets, and multiphase products.
- Existing literature presents conflicting reports on whether film breakup is stochastic or deterministic.
- Controlling and modeling multiphase product stability necessitates a deeper understanding of film rupture dynamics.
Purpose of the Study:
- To investigate the role of hydrodynamic versus capillary stresses in the dynamics of thin liquid films.
- To experimentally determine how varying flow conditions affect the rupture criteria of polymer solution films.
- To quantify the characteristics of thickness fluctuations and their influence on film breakup.
Main Methods:
- Utilized a modified thin film balance to control the ratio of hydrodynamic to capillary stresses.
- Experimentally varied pressure drop across planar polymer solution films to alter competing timescales.
- Employed visualization techniques to measure and quantify film thickness fluctuations under different flow strengths.
Main Results:
- Demonstrated that hydrodynamic forces can suppress thickness fluctuations within thin liquid films.
- Showed that the criteria for film rupture are dependent on hydrodynamic conditions.
- Observed a transition from stochastic to deterministic rupture as hydrodynamic forces become dominant.
Conclusions:
- Hydrodynamic forces play a critical role in determining the rupture mechanism of thin liquid films.
- The transition from stochastic to deterministic rupture is directly linked to the damping of thickness fluctuations by flow.
- This research provides new experimental insights into the fundamental processes governing thin film stability.
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