Polyimide composite fiber containing fluorine for respiratory monitoring and wearable electronics

The conductive fiber is a vital component for wearable devices to accurately monitor the health state of humans. However, the fabrication of flexible fiber-based sensors with high sensitivity still remains a challenge. Herein, we designed a wearable sensor based on fluorine-containing polyimide (PI) nanofiber coated with poly(3,4-ethylenedioxythiophene): poly(styrene sulfonic acid) (PEDOT:PSS) composites that derived from fluffy and multilayer PI nanofibrous aerogels. The performance of PI nanofibrous aerogels sensors can be properly adjusted by changing the relative proportion of hydrophilic and hydrophobic molecular units in molecular chains. The as-prepared sensors can accurately identify different states (normal breathing, deep breathing, rapid breathing, etc.) for respiratory monitoring. In particular, the fabricated sensor can realize effective detection of tiny humidity on the surface of human skin, and the longest detection distance can reach 3.5 cm. This work offers an insightful chemical strategy to design wearable moisture-sensitive sensors to realize human motion recognition, exercise status, and undisturbed respiratory monitoring.