3D Printing of Bioinspired Liquid Superrepellent Structures

Area of Science:

• Materials Science
• Surface Science
• Nanotechnology

Background:

• Bioinspired re-entrant structures offer liquid superrepellence, but struggle with low-surface-energy liquids.
• Existing fluorination-dependent surfaces often fail to repel liquids with surface tension below 15 mN m⁻¹.
• Overcoming this limitation is crucial for applications involving challenging solvents.

Purpose of the Study:

• To fabricate and characterize novel triply re-entrant structures for enhanced liquid superrepellence.
• To demonstrate superrepellence against a wide range of liquids, including those with extremely low surface energy.
• To explore the potential of these structures in microfluidic devices and other advanced applications.

Main Methods:

• Utilized two-photon polymerization based 3D printing to create triply re-entrant structures.
• Fabricated structures on both rigid and flexible substrates.
• Investigated liquid repellency for water and various organic liquids with surface tensions from 12.0 to 72.8 mN m⁻¹.

Main Results:

• Achieved superrepellence for water (72.8 mN m⁻¹) and organic liquids (12.0–27.1 mN m⁻¹).
• Demonstrated robust superrepellency on both rigid and flexible substrates, maintaining properties after oxygen plasma treatment.
• Constructed micro open capillaries for directional liquid spreading on the superrepellent surfaces.

Conclusions:

• Triply re-entrant structures fabricated via 3D printing effectively achieve superrepellence for diverse liquids, including low-surface-energy ones.
• The developed structures exhibit durability and versatility, suitable for rigid and flexible platforms.
• The ability to control liquid spreading opens possibilities for microfluidic platforms, lab-on-a-chip devices, and other technological applications.