Order-Disorder Structural Transitions in Mazes Built by Evaporating Drops.

Area of Science:

• Soft Matter Physics
• Materials Science
• Fluid Dynamics

Background:

• Surfactant solutions confined in porous media exhibit complex drying phenomena.
• Evaporation-driven pattern formation is observed across various scientific disciplines.

Purpose of the Study:

• To investigate the formation of labyrinthine patterns during the evaporation of surfactant solutions in quasi-two-dimensional porous media.
• To develop a model that explains the dynamics and structure of the resulting maze-like patterns.

Main Methods:

• Experimental observation of pattern formation during drying.
• Development and application of a cellular automaton model to simulate maze generation.
• Analysis of the influence of wettability heterogeneities and porous medium geometry.

Main Results:

• Micron-sized labyrinthine patterns form centimeter-sized mazes through sequential Haines jumps.
• The cellular automaton model accurately describes experimental maze formation dynamics and structure.
• Two geometric dimensionless quantities were identified as key controllers of maze structural order.

Conclusions:

• The study reveals a mechanism for generating complex maze structures from simple evaporation processes.
• The findings highlight the importance of pore-scale events and material properties in macroscopic pattern formation.
• The developed model provides a framework for understanding and predicting such structures in confined evaporating systems.