Bubble Printing of Liquid Metal Colloidal Particles for Conductive Patterns

Area of Science:

• Materials Science
• Nanotechnology
• Additive Manufacturing

Background:

• Bubble printing enables high-speed, high-precision patterning of micro/nanoparticles.
• Previous research primarily focused on patterning solid particles, with limited exploration of liquid particle patterning.

Purpose of the Study:

• To fabricate liquid metal wiring patterns using bubble printing with eutectic gallium–indium alloy (EGaIn) colloidal particles.
• To enhance the conductivity of the fabricated patterns through a galvanic replacement process.
• To evaluate the flexibility and conductivity of the resulting liquid metal wiring.

Main Methods:

• Utilizing a femtosecond laser to generate microbubbles for fixing EGaIn colloidal particles (≈0.7 µm diameter) on a glass substrate.
• Employing galvanic replacement to substitute gallium oxide with silver, rendering the wiring conductive.
• Optimizing laser power to achieve fine, continuous liquid metal lines with a width of 3.4 µm.

Main Results:

• Successfully fabricated continuous liquid metal wiring patterns with a line width of 3.4 µm.
• Achieved a conductivity of approximately 1.5 × 10^5 S/m for the liquid metal wiring.
• Demonstrated consistent conductivity even when the glass substrate was bent to a curvature of 0.02 m⁻¹.

Conclusions:

• Bubble printing is a viable method for fabricating flexible liquid metal wiring patterns.
• The combination of bubble printing and galvanic replacement offers a promising route for creating conductive micro/nanoscale structures.
• The developed technique holds potential for applications requiring flexible and conductive materials.