Laser-Engraved Liquid Metal Circuit for Wearable Electronics.

Area of Science:

• Materials Science
• Microfabrication
• Electronics Engineering

Background:

• Conventional methods for liquid metal (LM) circuit fabrication, like template methods, involve chemical etching, leading to long processing times, high costs, and complex multi-step procedures.
• These limitations hinder the rapid and cost-effective production of customized LM electronic circuits.

Purpose of the Study:

• To introduce a novel, reliable laser engraving micro-fabrication technology for personalized liquid metal electronic circuits.
• To demonstrate the capability of this method for creating high-resolution LM patterns on various substrates.

Main Methods:

• A digital pattern was used to guide a laser in burning grooves into a polyethylene (PE) film on a polydimethylsiloxane (PDMS) or paper substrate.
• Liquid metal was then introduced into the grooves, followed by removal of the PE film and encapsulation with a PDMS film.

Main Results:

• Precise patterned LM electronic circuits, including serpentine and Peano curves, were successfully fabricated.
• The minimum width and height of LM circuits achieved were 253 μm and 200 μm, respectively, with a minimum height of 26 μm on paper.
• The fabricated LM flexible circuits were integrated into a sensor device for successful heart rate detection.

Conclusions:

• Laser engraving offers a rapid, customizable, and high-resolution approach for fabricating LM circuit patterns.
• This micro-processing technology shows significant potential for the manufacturing of flexible electronic equipment and sensor devices.