A Robust Bridge‐Type Airflow Sensor Based on Flexible Superhydrophobic Carbon Nanotube Fiber Thin Films

Abstract Despite a great deal of research about airflow sensors by far, it is still hard to maintain ultra‐low limit of detection, short response, and recovery time under humid and rainy environment, which compromises its practical applications. Herein, a robust bridge‐type airflow sensor base on flexible superhydrophobic carbon nanotube fiber thin films is developed, which can not only own remarkable sensitive properties with ultra‐low limit of detection, fast response, and rapid recovery, but also exclude the influence of moisture or water drops in real applications. Both response time and recovery time are reduced compared with that of the previously reported flexible carbon‐based airflow sensors. Particularly, recovery time is reduced by ≈2/3. Meanwhile, the superhydrophobic structure renders normal functioning of the sensor in severe environment of high humidity or even in the rain, so that the influence of moisture and raindrops can be excluded, a property deficient in the previously reported airflow sensors. Not only can the sensor detect ambient airflow sensitively, but it also exhibits outstanding performance in respiratory health monitoring. Hence, the novel sensor designed in this work realizes operation in the environment of high humidity and rain, which tremendously uplifts the applicability of flexible sensors.