Controllable Three-Dimensional Well-Like Asymmetric Meniscus for Multiphase and Multimode Particle Manipulation

Area of Science:

• Microfluidics
• Interface Science
• Magnetic Manipulation

Background:

• Magnetic manipulation of multiphase particles is crucial in various fields.
• Current limitations exist in particle type and manipulation accuracy due to poor understanding of micronano interface mechanisms.

Purpose of the Study:

• To investigate the micronano interface mechanism for enhanced magnetic manipulation.
• To introduce a novel method for trapping and manipulating diverse multiphase particles.

Main Methods:

• Observation of a well-like asymmetric meniscus (WAM) formed around a tilted microneedle.
• Analysis of trap force generation from interface tension differences due to meniscus height gradient.
• Control of particle manipulation via microneedle tilt parameters (direction, angle) and array distance.

Main Results:

• The WAM enables trapping of various particles, including droplets and bubbles.
• Trap force is dependent on structural and kinematic parameters of the meniscus.
• Versatile manipulation strategies (capture-release, rotation, directional transport) were demonstrated.
• Bubble movement acceleration increased by over 900% with a 70% increase in meniscus height.

Conclusions:

• The WAM mechanism provides a new approach for precise magnetic manipulation of multiphase particles.
• This method offers significant improvements in particle manipulation efficiency and control.
• Potential applications include microchemical reactions and multiphase particle classification.