Scalable Strategy to Directly Prepare 2D and 3D Liquid Metal Circuits Based on Laser-Induced Selective Metallization

Abstract

Selective wetting of a gallium-based liquid metal on copper circuits is one of the ways to prepare liquid metal circuits. However, the complex fabrication processes of an adhesion layer between copper circuits (or patterns) and substrates were still inevitable, limiting scalable applications. Our work developed a facile way to directly prepare 2D and 3D liquid metal circuits by combining laser-induced selective metallization and selective wetting for the first time. The copper template was obtained on elastomers using laser-induced selective metallization, and high-resolution liquid metal circuits were fabricated by brushing Galinstan on the copper template in the alkali solution. The distribution of Cu element not only was on the top surface but also extended to the interior of the elastomer substrate. This revealed that the Cu layer prepared by laser-induced selective metallization is born to firmly embed into the substrate, which endowed the circuits with strong adhesion, reaching the highest 5B level. Moreover, the prepared liquid metal circuits (or patterns) had a typical layered structure. The liquid metal circuits exhibit good flexibility, stretchability, self-healing ability, and acid–alkaline resistance. Compared with the traditional methods of patterning liquid metals, fabricating liquid metal circuits based on laser-induced selective metallization has irreplaceable advantages, such as strong adhesion between circuits and substrate, fabricating 3D circuits, good acid–alkaline resistance, cost-effectiveness, maskless use, time savings, arbitrary design of patterns, and convenient operation, which endow this method with great application prospect.

Shaping a Soft Future: Patterning Liquid Metals

“…Then, LM (stripped of its surface oxide) will selectively remain within the areas of the metallic traces due to reactive wetting. [159,161]…”

Ultraviolet Laser-Induced Selective Metallization on White Polymers Using Oxygen Vacancy Laser Sensitizer for IoT Sensors

“…Currently, the laser sensitizer can be divided into two categories according to the mechanism of inducing ECP. 27 The first type is the mechanism of reduction. Laser activation makes laser sensitizers form metallic species, subsequently serving as the active center for initiating ECP.…”

Surface-Embedded Liquid Metal Electrodes with Abrasion Resistance via Direct Magnetic Printing

“…Despite the great progress of LM-based soft electronics, the construction of LM electronic interfaces with high mechanical reliability is still a challenge. To be specific, patterning of LM is a prerequisite to constructing functional circuits and electrodes for practical applications, which motivates the development of various patterning methods 24 such as direct writing, 25 selective wetting, 26 microfluidic injection, 27 and mechanical sintering. 28 However, these patterning methods can only deposit LM on the substrate surface or inside the substrate.…”