Anisotropic Electrowetting on Wrinkled Surfaces: Enhanced Wetting and Dependency on Initial Wetting State

Area of Science:

• Surface science
• Microfluidics
• Materials science

Background:

• Electrowetting on dielectric (EWOD) on microstructured surfaces is crucial for directional wetting in microfluidics.
• Understanding the influence of initial wetting states and anisotropy on EWOD is limited.

Purpose of the Study:

• Investigate initial wetting states and their impact on anisotropic electrowetting.
• Explore droplet behavior on wrinkled EWOD platforms.

Main Methods:

• Fabricated wrinkled surfaces using a stampless and maskless technique.
• Modulated wrinkle topography to alter interfacial wetting conditions.
• Studied droplet behavior under electrowetting on the fabricated surfaces.

Main Results:

• Demonstrated capillary wicking-assisted electrowetting in a specific direction dictated by ordered wrinkles.
• Observed enhanced droplet spreading due to directional electrowetting.
• Found that conformal wetting states enhance unidirectional electrowetting, while composite wetting states reverse anisotropy.

Conclusions:

• Initial wetting states and surface topography critically affect anisotropic electrowetting.
• Wrinkled EWOD platforms offer tunable directional wetting for microfluidic applications.
• The study provides insights into controlling droplet behavior through surface engineering.