Additive-Free Continuous, Weavable Carbon Nanotube Fibers as Wearable Multifunctional Gas Sensor

Flexible chemical sensors based on carbon nanomaterials must possess high electrical conductivity, sensitivity to analytes, mechanical flexibility, and durability for effective toxic gas detection and resilience during movement. In this study, we developed a method to produce continuous, additive-free, and weavable carbon nanotube (CNT) fibers at a remarkable production rate of approximately 339 m/h, using a floating catalyst (FC) chemical vapor deposition (CVD) process for wearable sensing applications. These CNT fibers were generated by spinning CNT aerogel through a water bath, and they exhibited exceptional characteristics such as high porosity, electrical conductivity, a strain-to-failure of approximately 16%, and a Young's modulus of around 1.4 GPa. We then seamlessly integrated these fibers into commercial polyester fabric. Remarkably, they displayed high sensitivity to volatile organic compounds and toxic gases at room temperature, boasting a detection limit of approximately 50 parts per billion, and a rapid response time of under 30 s, with the exception of nitric oxide (NO) and hydrogen sulfide ( $\text{H}_{{2}}\text{S}$ ) (with response times of around 200 s). Notably, these CNT fibers maintained their gas sensing capabilities even under various distortions such as bending, twisting, and knotting, making them exceptionally suitable for incorporation into the fabric for gas sensing applications. The successful synthesis, weaving, and impressive gas-sensing performance of these long CNT fibers underscore their suitability as wearable sensors. Moreover, the scalable, additive-free synthesis method holds significant promise for the mass production of wearable sensing devices.