Stability of a liquid bridge between nonparallel hydrophilic surfaces

Area of Science:

• Fluid dynamics
• Surface science
• Materials science

Background:

• Liquid bridges form between surfaces in various industrial and natural processes, such as printing.
• Non-parallel surfaces with a dihedral angle (ψ) can lead to liquid bridge instability if ψ exceeds a critical angle (ψ_c).
• Unstable liquid bridges propel towards the surfaces' cusp.

Purpose of the Study:

• To systematically investigate parameters influencing the critical angle (ψ_c) for liquid bridge stability.
• To establish a quantitative relationship between surface properties and liquid bridge stability.
• To develop a predictive model for critical angle in different liquid bridge formation scenarios.

Main Methods:

• Combined experimental, theoretical, and numerical investigations.
• Systematic study of parameters affecting critical angle (ψ_c).
• Analysis of advancing contact angle (θ_a) and Contact Angle Hysteresis (CAH) effects.

Main Results:

• The critical angle (ψ_c) is determined by advancing contact angle (θ_a) and Contact Angle Hysteresis (CAH).
• ψ_c increases with increasing θ_a or CAH, demonstrating a nonlinear and interdependent influence.
• An empirical equation, ψ_c=f(θ_a,CAH), was derived to predict the critical angle.

Conclusions:

• The stability of liquid bridges between non-parallel surfaces is quantifiable through surface properties.
• The developed empirical equation provides a tool for predicting critical angles in diverse liquid bridge configurations.
• Understanding these parameters is crucial for controlling liquid bridge behavior in applications like printing.