3D-Printed Bioinspired Cassie-Baxter Wettability for Controllable Microdroplet Manipulation

Area of Science:

• Materials Science
• Surface Science
• Biomimetics

Background:

• Fabricating surfaces with tunable Cassie-Baxter wettability, adjustable from hydrophilic to superhydrophobic, presents a significant challenge.
• Existing methods often lack precise control over wettability through geometric parameter modification.
• Bioinspired surfaces offer promising avenues for advanced material functionalities.

Purpose of the Study:

• To propose and demonstrate a bioinspired surface with continuously adjustable Cassie-Baxter wettability using projection micro-stereolithography (PμSL).
• To achieve precise control over water contact angle (CA) and adhesion force by altering geometric parameters.
• To explore potential applications of these tunable surfaces.

Main Methods:

• Fabrication of a bioinspired textured surface using projection micro-stereolithography (PμSL) 3D printing.
• Characterization of surface wettability, measuring contact angles (CA) and adhesion forces.
• Utilizing a multi-phase lattice Boltzmann model to investigate the mechanisms of CA control.

Main Results:

• Achieved a maximum contact angle (CA) of 171°, surpassing that of natural omniphobic surfaces.
• Demonstrated continuous control of CA in the range of 55-171° and adhesion force from 71 to 99 μN by adjusting geometric parameters.
• Identified the underlying mechanisms governing CA control through simulation.

Conclusions:

• Successfully fabricated a bioinspired surface with tunable Cassie-Baxter wettability using PμSL 3D printing.
• The developed surface offers precise control over wettability and adhesion, mimicking and exceeding natural examples.
• Potential applications include microreactors, efficient water transport, and droplet manipulation, paving the way for next-generation functional surfaces.