Flexible strain sensor based on aerogel-spun carbon nanotube yarn with a core-sheath structure

Flexible strain sensors with good linear sensitivity, mechanical compatibility with systems and robustness over repeated usages are very desirable in wearable electronics, smart textiles, and other multifunctional structures. To this end, carbon nanotube/polyvinyl alcohol (CNT/PVA) coated yarn with a core-sheath structure (inner pure CNT core and outer CNT-PVA sheath) was fabricated by dipping the aerogel-spun CNT yarn in various PVA solutions for a short period of time. The as-produced CNT/PVA coated yarn has an electrical conductivity of 447.1 S/cm and exhibits a linear piezoresistive response, with a high gauge factor (the ratio of electrical resistance change to strain change) of 2.36. Compared with the pure CNT yarn, the PVA coated yarn has an improved tensile strength by 71.8%, Young's modulus by 157.3%, abrasion-resistance by 100%, and enhanced stability after cyclic loading. This demonstrates a promising strain sensor for system integration into flexible intelligent devices or other advanced composites.