Robust and Transparent Lossless Directional Omniphobic Ultra-Thin Sticker-Type Film with Re-entrant Micro-Stripe...

Area of Science:

• Surface Engineering and Materials Science
• Microfluidics and Nanotechnology

Background:

• Controlled droplet movement without surface wetting is crucial for advanced applications like biological analyses and green technology.
• Existing robust, transparent, and portable directional omniphobic films for microfluidic platforms are limited.

Purpose of the Study:

• To report a novel perfluoropolyether (PFPE) directional omniphobic film (PDOF) for anisotropic liquid droplet control.
• To demonstrate the fabrication and properties of a sticker-type film for portable microfluidic applications.

Main Methods:

• Fabrication of an ultra-thin (56 μm) PDOF using perfluoropolyether (PFPE) via a soft-molding process with adhesion engineering.
• Incorporation of re-entrant micro-stripe structures on the PFPE surface to induce directional sliding.
• Characterization of the film's transparency, robustness, and liquid droplet manipulation capabilities.

Main Results:

• The fabricated PFPE-based PDOF exhibits excellent transparency and robustness.
• The film effectively controls the anisotropic sliding of various liquid droplets.
• Liquid sliding properties are tunable based on the direction and spacing of the surface microstructures, defined as an anisotropic factor.

Conclusions:

• The developed PFPE directional omniphobic film offers a promising solution for precise liquid control in portable microfluidic devices.
• PFPE's chemical stability and turgidity make it a superior alternative to PDMS for fabricating such advanced films.
• The study highlights the potential of engineered surface microstructures for advanced directional liquid manipulation.