Prefilled Thumbtack-Shaped Micropillar Array for Liquid Metal Spreading on Intrinsically Nonwetting Surfaces

Area of Science:

• Materials Science
• Surface Engineering
• Microfluidics

Background:

• Liquid metals offer excellent electrical and thermal properties for electronics and energy.
• High surface tension causes poor wettability and limited spreading on conventional substrates.
• Overcoming wettability challenges is crucial for expanding liquid metal applications.

Purpose of the Study:

• To develop a microstructured surface that enhances liquid metal wettability and spreading.
• To create a stable platform for uniform liquid metal films.
• To investigate the performance of liquid metal films on structured surfaces under various conditions.

Main Methods:

• Fabrication of a surface with a triangular array of thumbtack-shaped micropillars.
• Vacuum-filling method to impregnate the microstructured substrate with liquid metal.
• Experimental evaluation of apparent contact angle, stability, refilling, and film flow dynamics.

Main Results:

• Achieved a significant reduction in apparent contact angle from 140° to below 20°.
• Demonstrated excellent stability against oscillation and inversion, with easy refilling.
• Required lower flow rates for uniform film formation compared to flat substrates.
• Maintained complete coverage and sustained spreading under turbulence and magnetic resistance.

Conclusions:

• The prefilled microstructured substrate (PFMS) effectively enhances liquid metal wetting and spreading.
• PFMS provides a stable and robust platform for liquid metal applications in demanding environments.
• The developed technology shows significant potential for advanced electronics and energy systems.