Hundred-Nanometer-Thick Stretchable Liquid Metal Films for Ultra-Conformal Bioelectrodes

Area of Science:

• Materials Science and Engineering
• Bioelectronics
• Nanotechnology

Background:

• Epidermal electrodes offer high-fidelity electrophysiological monitoring due to conformability.
• Challenges exist in creating ultrathin, highly conductive films for seamless skin integration and improved signal quality under dynamic conditions.

Purpose of the Study:

• To develop an ultrathin, highly conductive liquid metal (LM) film for epidermal bioelectrodes.
• To achieve superior skin conformability and enhanced signal-to-noise ratios for dynamic electrophysiological monitoring.

Main Methods:

• Fabrication of a ≈200 nm-thick liquid metal conductive film, resulting in a 1.1 µm total electrode thickness.
• Utilized a synergistic deposition strategy combining in situ substrate precooling with thermal evaporation for nanoscale control.
• Suppressed dewetting behavior via low-temperature stabilization to achieve defect-free nano-conductive films (minimum 19 nm).

Main Results:

• Achieved exceptional conductivity (3×10⁶ S·m⁻¹) without mechanical activation.
• Demonstrated outstanding skin conformability and ultralow interfacial impedance (8.5 kΩ at 1 kHz).
• Enabled medical-grade electromyographic signal monitoring during motion with remarkable dynamic stability.

Conclusions:

• The novel thermal-low temperature deposition strategy enables precise control over ultrathin, highly conductive LM films.
• The fabricated epidermal bioelectrode exhibits excellent performance characteristics for wearable bioelectronic applications.
• This advancement holds significant potential for next-generation wearable sensors and medical monitoring devices.