Double-Layered Microcracks Coupled Strain Sensors with High Sensitivity and Wide Working Range

Area of Science:

• Materials Science
• Nanotechnology
• Wearable Technology

Background:

• Flexible strain sensors are vital for wearable technology and physiological monitoring.
• Nanomaterial thin films offer good performance but face challenges with crack propagation and sensitivity.
• Existing sensors struggle with limited working ranges due to crack expansion in rigid films.

Purpose of the Study:

• To develop a novel conductive strategy for flexible strain sensors using double-layered microcracks.
• To enhance sensor sensitivity, working range, and stability.
• To demonstrate the sensor's utility in human health monitoring and human-machine interaction.

Main Methods:

• Fabrication of gold/Polypyrrole (PPy) composite films with double-layered microcracks.
• Characterization of crack formation and sensing mechanisms.
• Evaluation of sensor performance including gauge factor, working range, strain resolution, and cycling stability.

Main Results:

• The developed strain sensor achieved an ultrahigh gauge factor (GF) of ≈3.604 × 10^7.
• An expansive working range from 0% to 60% strain was achieved.
• High strain resolution (0.02%) and excellent cycling stability were demonstrated.

Conclusions:

• Double-layered microcracks in gold/PPy composites significantly enhance strain sensing performance.
• The developed sensor is practical for real-time monitoring of vital signs, body motions, weight, and sounds.
• This technology holds promise for advanced human health monitoring and human-machine interfaces.