Controlling the oxidation and wettability of liquid metal via femtosecond laser for high-resolution flexible electronics

Abstract

Liquid metal-based electronic devices are attracting increasing attention owing to their excellent flexibility and high conductivity. However, a simple way to realize liquid metal electronics on a microscale without photolithography is still challenging. Herein, the wettability and adhesion of liquid metal are controlled by combining the stirring method, femtosecond laser microfabrication, and sacrificial layer assistant. The adhesive force of liquid metal is dramatically enhanced by adjusting its oxidation. The wetting area is limited to a micro-pattern by a femtosecond laser and sacrificial layer. On this basis, a high-resolution liquid metal printing method is proposed. The printing resolution can be controlled even less than 50 μm. The resultant liquid metal pattern is applied to electronic skin, which shows uniformity, flexibility, and stability. It is anticipated that this liquid metal printing method will hold great promise in the fields of flexible electronics.

Interfacial interaction-induced super-wettability of gallium-based liquid metals: a review

“…The surface of polydimethylsiloxane (PDMS) substrate was selectively treated using femtosecond laser and sacrificial layer. 24 The scanned areas show ultra-low adhesion to LM while the untreated areas maintain high adhesion to LM. Fig.…”

Facile printing of liquid–metal-based stretchable conductor using EGaIn/Ga2O3 composite

“…However, in our experiment, EGaIn/Ga 2 O 3 could easily form a uniform paste with just gentle hand mixing. We attribute this ease to the miscibility of Ga 2 O 3 and the native oxidation layer of EGaIn, enabling the LM to easily wet the surface of Ga 2 O 3 particles [28,29].…”

Printed Bilayer Liquid Metal Soft Sensors for Strain and Tactile Perception in Soft Robotics

“…The poor printability issue of the bare EGaIn can be addressed by converting EGaIn into paste-like oxidized EGaIn (o-EGaIn) by mixing it with air, which includes a large amount of Ga 2 O 3 oxidation layers that alter its rheology, resulting in improved printability on various substrates (Figure 1c; and Figure S1, Supporting Information). [30][31][32] However, o-EGaIn demonstrates limited mechanical stability, particularly under large deformations over 100% strain, making it challenging to apply as sensors (Figure S2, Supporting Information). We designed a bilayer LM-based soft sensor to overcome this trade-off between printability and mechanical stability.…”

“…[26,27] Mixing LM with other solid micro/nanoparticles can create a biphasic paste-like conductor with good printability, which is considered a promising approach, however, this approach results in a compromise in terms of mechanical durability. [28][29][30] Despite these efforts, there is a lack of a straightforward method to achieve high-performance LM-based soft sensors.…”