Interfacial Electrochemical Polymerization for Spinning Liquid Metals into Core-Shell Wires

Area of Science:

• Materials Science
• Electrochemistry
• Soft Robotics

Background:

• Metal wires are crucial for 3D printing, soft electronics, optics, and metamaterials.
• Gallium-based liquid metals (EGaIn) offer conductivity, fluidity, and biocompatibility but are difficult to spin due to low viscosity and high surface tension.

Purpose of the Study:

• To develop a method for spinning liquid metal wires with enhanced stability and mechanical properties.
• To create stretchable and conductive EGaIn wires for advanced sensor applications.

Main Methods:

• Utilized EGaIn as a working electrode to induce electrochemical polymerization of monomers, forming stabilizing polymer shells.
• Employed electrowetting and electrocapillarity to reduce surface tension during the spinning process.
• Encapsulated the polymer-shelled EGaIn wires into elastomers to achieve high stretchability and conductivity.

Main Results:

• Successfully spun EGaIn into wires with tunable polymer shell thicknesses (0.6-30 μm) and diameters (90-300 μm).
• Achieved highly stretchable (up to 800%) and conductive (1.5 × 10^6 S m^-1) elastic EGaIn wires.
• Demonstrated the wires' capability as sensitive and durable wearable sensors for various applications, including gesture recognition with machine learning.

Conclusions:

• The electrochemical polymerization method effectively stabilizes liquid metal spinning, overcoming inherent challenges.
• The resulting elastic EGaIn wires represent a significant advancement for wearable electronics and sensing technologies.
• This work opens new avenues for fabricating robust, stretchable conductors for diverse technological applications.