Wettability control of micropore-array films by altering the surface nanostructures

Area of Science:

• Materials Science
• Surface Chemistry
• Nanotechnology

Background:

• Controlling surface wettability is crucial for various applications.
• Film wettability is typically tuned by chemical composition or macrostructure.
• Nanostructure offers a potential route for fine-tuning surface properties.

Purpose of the Study:

• To investigate the effect of surface nanostructure on the wettability of porous films.
• To explore methods for tuning wettability from hydrophilic to superhydrophobic without altering chemical composition.
• To evaluate the potential for creating patterned wettability using UV irradiation.

Main Methods:

• Fabrication of porous films (PA1 and PA2) with different ZnO nanostructures (horizontal nanosheets vs. vertical nanorods).
• Contact angle measurements to quantify wettability.
• Analysis of nanostructure shape, orientation, and micropore size effects on PA1 films.
• Investigation of UV irradiation-induced wettability transitions in PA1 films.

Main Results:

• PA1 films with horizontal ZnO nanosheets exhibited nearly superhydrophobic behavior.
• PA2 films with vertically-aligned ZnO nanorods were hydrophilic.
• Nanostructure shape, orientation, and micropore size significantly influenced the contact angle of PA1 films.
• PA1 films showed reversible wettability transitions upon UV irradiation.
• Selective UV irradiation enabled the creation of radial wettability patterns.

Conclusions:

• Surface nanostructure is a key factor in controlling film wettability, independent of chemical composition.
• Tailoring nanostructure offers a versatile approach to achieve tunable and patterned wettability in porous films.
• UV-induced reversible wettability transition presents a novel method for creating functional surface patterns.