Wet-Pulling Method Induced Self-Folding Layered CNT/WPU Fiber Strain Sensor with Ultrahigh Sensitivity and Wide...

Area of Science:

• Materials Science
• Flexible Electronics
• Nanotechnology

Background:

• Flexible electronics require highly sensitive, durable strain sensors for human activity monitoring.
• Conventional sensors face a trade-off between sensitivity and stretchability.
• There is a need for advanced materials to overcome these limitations.

Purpose of the Study:

• To develop a novel strain sensor overcoming the sensitivity-stretchability limitations.
• To create a carbon nanotube/waterborne polyurethane composite fiber.
• To achieve high performance and durability for wearable applications.

Main Methods:

• Fabrication of a carbon nanotube (CNT)/waterborne polyurethane (WPU) composite fiber using a novel wet-pulling method.
• Layer-by-layer structure formation with synergistic interactions and surface crack engineering.
• Characterization of the sensor's sensitivity, detection range, response time, and cyclic stability.

Main Results:

• Achieved an ultrahigh gauge factor (GF = 117222.64) across a wide working range (243.78% strain).
• Demonstrated rapid dynamic response (60 ms response time, 80 ms relaxation time) and excellent cyclic stability (>6000 cycles).
• Accurately monitored subtle physiological signals and large-scale joint movements, with potential for encrypted message transmission.

Conclusions:

• The developed CNT/WPU composite fiber sensor overcomes the sensitivity-stretchability trade-off.
• The novel wet-pulling method and engineered structure enable high performance and reliability.
• This scalable and cost-effective strategy paves the way for next-generation wearable sensors.