Evaporation-Driven Solutal Marangoni Control of Rayleigh-Taylor Instability in Inverted Films

Area of Science:

• Fluid dynamics
• Interfacial phenomena
• Materials science

Background:

• Inverted liquid films are prone to rupture due to gravity-driven Rayleigh-Taylor instability (RTI).
• Controlling interfacial dynamics is crucial for applications involving thin films.

Purpose of the Study:

• To investigate the use of selective evaporation to suppress or modify RTI in inverted liquid films.
• To understand the role of solutal Marangoni stresses in stabilizing these films.

Main Methods:

• Systematic experimental studies using high-resolution deflectometry to track film evolution.
• Development of a complementary theoretical model incorporating gravity, capillarity, and Marangoni forces.
• Analysis of instability regimes based on volatility, viscosity, and surface tension contrast.

Main Results:

• Identified three distinct instability regimes: promotion, suppression, and sustained oscillations.
• Demonstrated that solutal Marangoni stresses induced by selective evaporation can effectively suppress RTI.
• Achieved quantitative agreement between experimental measurements and theoretical predictions.

Conclusions:

• Evaporation-driven Marangoni flow is a robust strategy for controlling interfacial instability in inverted films.
• First systematic experimental validation of solutal-Marangoni suppression of RTI in inverted configurations.
• Provides a general framework for instability control in volatile thin films with implications for materials processing and soft-matter hydrodynamics.