Highly responsive core-shell microactuator arrays for use in viscous and viscoelastic fluids

Area of Science:

• Materials Science
• Microfabrication
• Robotics

Background:

• Development of microscale actuators is crucial for advanced applications.
• Existing magnetic microactuators often have limitations in responsiveness and control.
• Core-shell structures offer potential for decoupling material properties.

Purpose of the Study:

• To present a novel fabrication method for polymer-metal core-shell magnetic microactuators.
• To demonstrate the tunability of actuator response by adjusting core-shell geometry.
• To evaluate the performance of these microactuators in viscous fluid manipulation.

Main Methods:

• Electrochemical fabrication of microstructures within particle track-etched membranes.
• Creation of core-shell structures with a poly(dimethylsiloxane) core and a nickel shell.
• Characterization of microactuator dimensions (10 μm length, 550 nm diameter) and shell thickness (100 nm Ni on upper 3-8 μm).

Main Results:

• Achieved nearly 90° deflection with moderate magnetic fields.
• Demonstrated the ability to drive fluid flow in a fluid 550 times more viscous than water.
• Decoupled elastic and magnetic components for optimized actuator response via geometry.

Conclusions:

• The presented fabrication method yields highly responsive magnetic microactuators.
• Core-shell geometry optimization allows for tunable actuator performance.
• These microactuators show promise for applications involving manipulation in highly viscous media.