Instability of the Contact Line between Three Fluid Phases during Mass Transfer Processes

Area of Science:

• Fluid dynamics
• Interface science
• Physical chemistry

Background:

• The behavior of the movable contact line is governed by surface tensions, contact angles, hydrostatic pressure, and Laplace capillary pressure.
• Changes in concentration and temperature affect interface and surface tension, influencing contact line stability.
• Mass transport processes can lead to various forms of contact line instability.

Purpose of the Study:

• To investigate the instability phenomena of the three-phase contact line.
• To identify the factors causing contact line deformation and oscillations.
• To understand the practical implications of contact line behavior in coalescence and emulsification.

Main Methods:

• Analysis of force equilibrium at the contact line.
• Observation of contact line shape and interface dynamics.
• Study of mass transport effects on contact line stability.

Main Results:

• The three-phase contact line is sensitive to disturbances in force equilibrium.
• Instabilities include oscillations, single bulges, traveling deformations, and periodically generated damped deformations.
• These instabilities are linked to changes in concentration and temperature during mass transport.

Conclusions:

• The instability of the three-phase contact line is a key factor in processes like liquid coalescence and spontaneous emulsification.
• Understanding these instabilities is crucial for controlling interfacial phenomena in various applications.
• The study highlights the dynamic nature of contact lines under varying physical and chemical conditions.