Highly stretchable, durable, and superfine fiber-shaped strain sensor with a porous core-sheath microstructure

A stretchable fiber-shaped strain sensor benefits from its high aspect ratio and can be easily integrated into textiles, which has attracted extensive attention. Introducing microstructures such as porous or buckling mi-crostructures into elastic fibers are often used to obtain high-performance strain-sensing fibers. However, the fabrication of high-performance superfine fiber-shaped strain sensor still faces the difficulty of preparing controllable microstructures on the surface of the fiber. In this work, we propose a breath figure method to fabricate CNTs/SEBS film with porous microstructure on the polyurethane fiber (PU fiber). By adjusting the process parameters, the morphology of the porous microstructure can be controlled conveniently. The optimized fiber-shaped strain sensor has a superfine diameter (58 mu m), large detection range (240%), low strain detection limit (0.025%), high sensitivity (GF of 1439.83 at 230 %-250%), fast response time (approximate to 62.7 ms), and excellent stability with 100,000 cycles at a large deformation of 100%. Finally, the fiber-shape strain sensor was sewn into the textile to verify its application in gesture recognition, breath sensing and limbs activity monitoring. This work proposes a simple and efficient strategy to realize the superfine fiber-shaped strain sensor with controlled porous microstructure, which has great potential in the field of wearable electronic devices.