Ladderlike Conical Micropillars Facilitating Underwater Gas-Bubble Manipulation in an Aqueous Environment

Area of Science:

• Fluid Dynamics
• Materials Science
• Surface Science

Background:

• Underwater gas bubble manipulation is crucial for industrial and academic applications.
• Transporting gas bubbles in three-dimensional (3D) space presents significant challenges.
• Existing methods for directional gas bubble transport are limited in scope and applicability.

Purpose of the Study:

• To propose novel tapered pillar structures for manipulating underwater gas bubbles.
• To develop advanced fabrication techniques for these unique structures.
• To investigate and enhance the aerophilic properties for efficient gas bubble transport.

Main Methods:

• Fabrication of ladderlike and helical ladderlike tapered pillars using an improved coating and etching method.
• Development of a modified gas-bubble slippery technology to enhance aerophilicity.
• Analysis of gas bubble dynamics using high-speed cameras to study transport mechanisms.

Main Results:

• Identified Laplace force, arising from geometry gradients, as a key factor in controlling gas bubble velocity.
• Achieved tunable transport velocities ranging from 113.9 ± 10.3 to 309.1 ± 5.8 mm/s by adjusting pillar wettability, tilt angle, and geometry.
• Successfully demonstrated 3D directional gas bubble transport using a fabricated helical ladderlike tapered pillar.

Conclusions:

• The developed tapered pillars offer a systematic approach for designing structures for 3D underwater gas bubble transport.
• The findings provide a new pathway for creating advanced materials and structures for fluid manipulation.
• This research advances the capabilities in controlled underwater gas bubble dynamics for various applications.