Bioinspired ultrahigh water pinning nanostructures.

Area of Science:

• Materials Science
• Surface Science
• Nanotechnology

Background:

• The coffee ring effect causes uneven deposition from drying droplets.
• Controlling liquid droplet behavior on surfaces is crucial for various applications.

Purpose of the Study:

• To fabricate surfaces with ultrahigh water pinning forces.
• To investigate the relationship between surface topography and water pinning.
• To demonstrate the mitigation of the coffee ring effect.

Main Methods:

• Nanoimprinting of polymer films (polycarbonate).
• Systematic variation of surface topographical designs.
• Measurement of water pinning forces.

Main Results:

• Achieved ultrahigh water pinning forces (104–690 μN) on polycarbonate films.
• Identified optimal surface designs combining conical/parabolic and isotropic/continuous nanoprotrusions.
• Demonstrated mitigation of the coffee ring effect using engineered surfaces.

Conclusions:

• Specific nanostructure designs enable ultrahigh water pinning forces.
• These surfaces offer a rule-of-thumb for engineering tunable water pinning.
• Engineered surfaces can effectively reduce the coffee ring effect.