Design of open systems for meniscus splitting demonstrated using an aqueous polymer solution.

Area of Science:

• Soft matter physics
• Materials science
• Chemical engineering

Background:

• Open systems on soft material surfaces can create dissipative structures.
• Evaporative self-organization is a key phenomenon in these systems.
• Viscous fingering is a known instability in fluid dynamics.

Purpose of the Study:

• To demonstrate and analyze meniscus splitting in polyvinyl alcohol (PVA) solutions.
• To investigate pattern formation driven by evaporation in soft materials.
• To understand the universality of this phenomenon across different polymer species.

Main Methods:

• Utilized a Hele-Shaw cell to confine an aqueous PVA solution.
• Controlled evaporation by manipulating local humidity gradients.
• Analyzed interface deformation and polymer deposition patterns.
• Investigated concentration-dependent viscosity changes in PVA solutions.

Main Results:

• Observed meniscus splitting phenomena driven by evaporation in PVA solutions.
• Demonstrated that PVA solutions can form vertical membranes by bridging the cell gap.
• Showed that interfacial shape transformation is controllable by polymer properties and evaporation atmosphere.
• Identified a steep concentration-dependent viscosity gradient under humidity gradients.

Conclusions:

• Meniscus splitting is a universal phenomenon in soft material evaporation, controllable via external conditions.
• This study provides a strategy for non-equilibrium phenomena using soft materials, particles, fibers, and networks.
• Future work can explore this phenomenon with different cell designs and chemical species.