A Liquid Metal-Embedded Sheath-Core Fiber with Internal Helical Structure for Strain-Insensitive Electronics

Area of Science:

• Materials Science
• Nanotechnology
• Wearable Electronics

Background:

• Stable conductivity is essential for flexible wearable devices, but achieving high elasticity, conductivity, and stability simultaneously is challenging.
• Existing materials often compromise on one or more of these critical properties.

Purpose of the Study:

• To develop a novel core-sheath fiber with enhanced stretchability, conductivity, and strain-insensitivity for wearable applications.
• To overcome the limitations of current materials in flexible electronic devices.

Main Methods:

• Fabrication of a hollow fiber with an internal helical structure using coaxial wet-spinning.
• Infusion of liquid metal into the helical channel to achieve ultra-conductivity.
• Characterization of mechanical properties, conductivity, strain-insensitivity, and stability.

Main Results:

• Achieved high stretchability with an elongation at break of ≈1440%.
• Obtained ultra-conductivity of 1.94 × 10⁵ S m^-1.
• Demonstrated outstanding strain-insensitivity (resistance variation <1.6% at 100% strain) and stability.
• Showcased potential in joule heaters, NFC, and wireless charging applications.

Conclusions:

• The novel core-sheath fiber effectively combines high elasticity, ultra-conductivity, and strain-insensitivity.
• The helical structure and liquid metal infusion are key to achieving superior performance.
• These fibers offer a promising solution for advanced flexible wearable devices and integrated electronic textiles.