Highly sensitive strain sensor with wide strain range fabricated using carbonized natural wrapping yarns

In this work, we report a high-performance strain sensor with ultra-sensitivity under the subtle strain and large sensing strain range based on Ecoflex rubber and carbonized natural yarns. The flexible strain sensor based on wrapping yarn with carbon nanofiber yarn as sheath and natural silk yarn as core can capture ultralow detection limit (<0.01%) with a high gage factor of 307 and the excellent cycling stability. The wrapping yarn fabricated using cotton yarn as sheath and silk yarn as core endowed the sensor with wide strain range from 0.1% to 130%, high sensitivity for the subtle deformation, quick response time (<400 ms) and durability. Remarkably, the sensor can not only monitor the various human motions and physiological information, such as walking, breathing, pulses, speaking, but also distinguish the sound wave and damped vibration for structural safety. It is hopeful to develop the multifunctional strain sensors for widespread applications.