Meniscus instabilities in thin elastic layers.

Area of Science:

• Materials Science
• Solid Mechanics
• Fluid Dynamics

Background:

• Thin elastic layers confined between stiffer bodies can exhibit meniscus instabilities.
• Receding free boundaries of elastic layers can lead to air invasion through elastic instability.
• Understanding these instabilities is crucial for applications involving thin films and interfaces.

Purpose of the Study:

• To investigate the nature of meniscus instabilities in thin elastic layers under various loading conditions.
• To determine the critical conditions and characteristic wavelength of air fingering during meniscus recession.
• To demonstrate the universality of the instability form across different scenarios.

Main Methods:

• Theoretical analysis of elastic instabilities in confined thin layers.
• Modeling meniscus recession and air invasion phenomena.
• Calculation of instability thresholds for different geometries, including wedges and peeling plates.

Main Results:

• The form of the meniscus instability is independent of loading conditions when the meniscus thickness is small.
• Instability occurs when the meniscus has receded by approximately 1.27 times its thickness (a).
• The characteristic wavelength of the air fingers is predicted to be approximately 2.75 times the meniscus thickness (λ ≈ 2.75a).

Conclusions:

• A universal elastic instability governs air fingering in receding menisci of thin elastic layers.
• The critical recession distance and instability wavelength are primarily dependent on the meniscus thickness.
• The findings provide a predictive framework for elastic-layer instabilities in diverse mechanical configurations.