High-Performance Auxetic Bilayer Conductive Mesh-Based Multi-Material Integrated Stretchable Strain Sensors

Area of Science:

• Materials Science
• Nanotechnology
• Wearable Technology

Background:

• High-performance stretchable strain sensors are crucial for advanced wearable devices.
• Existing sensors often struggle with a balance between sensitivity and sensing range.

Purpose of the Study:

• To develop a novel auxetic bilayer conductive mesh strain sensor (ABSS) with enhanced sensitivity and a broad sensing range.
• To investigate the synergistic effects of material composition and structural design on sensor performance.

Main Methods:

• Fabrication of the ABSS using direct ink writing 3D printing and ink spraying.
• Utilizing a bilayer conductive mesh of single-walled carbon nanotubes (SWCNTs) and carbon-black-doped Ecoflex silicone rubber.
• Incorporating a high-hardness auxetic frame to enhance strain concentration and crack formation.

Main Results:

• The ABSS demonstrated a high gauge factor of approximately 13.4, significantly outperforming common sensors.
• The sensor exhibited excellent performance across the full strain range due to crack generation in SWCNTs and maintained conductivity.
• The auxetic structure facilitated longitudinal SWCNT crack formation, boosting sensor sensitivity.

Conclusions:

• The developed ABSS shows superior performance for wearable applications, including motion and physiological monitoring.
• The synergistic design of the bilayer mesh and auxetic structure is key to achieving high sensitivity and a broad sensing range.
• This work presents a promising pathway for next-generation wearable electronic devices.