Characterization of wetting using topological principles.

Area of Science:

• Surface science and physical chemistry.
• Multiphase flow and fluid dynamics.
• Topological physics and geometry.

Background:

• Wetting behavior is crucial for natural phenomena and technological applications.
• Traditional contact angle measurements, based on geometrical curvature and Young's equation, face limitations in complex systems.
• The representativeness of contact angle for intricate wetting scenarios remains an open question.

Purpose of the Study:

• To introduce and validate a novel topological principle for characterizing wetting states.
• To assess the robustness and sensitivity of this topological approach against traditional methods.
• To explore the potential of topological concepts for studying complex multiphase systems.

Main Methods:

• Introduction of a macroscopic contact angle derived from the deficit curvature of fluid interfaces.
• Sessile droplet simulations and multiphase experiments on porous materials (sintered glass, Bentheimer sandstone).
• Comparative analysis with traditional contact angle measurement techniques.

Main Results:

• The topological principle aligns with thermodynamic principles under simple conditions.
• The proposed approach yields results comparable to local contact angle measurements at high image resolutions.
• At lower resolutions, the topological method demonstrates superior accuracy and robustness against resolution-dependent artifacts.

Conclusions:

• The developed topological approach provides a more accurate and robust measure of wetting in complex systems.
• This method offers advantages over traditional contact angle measurements, especially under varying resolution conditions.
• The study opens new avenues for characterizing wetting in complex systems and advancing theoretical understanding of multiphase phenomena.