A flexible, sensitive and stable humidity sensor based on an all-polymer nanofiber film

A flexible humidity sensor with high sensitivity and reliability is reported by introducing poly(triphenylamine) (PTPA) into poly(vinylidene fluoride)(PVDF) nanofibers (NFs) via electrospinning. Combined experiments and theoretical studies show that the addition of conductive PTPA enhances the dielectric constant and moisture adsorption, owing to the rough NF surfaces and PTPA–water interactions. The PVDF/PTPA NF film exhibits a wide sensing range (20–90 %RH), short response/recovery time (33/28 s), good recoverability and long-term stability (over 100 cycles), outperforming most reported polymer-based humidity sensors. This work opens up a new route for sensitive, flexible and reliable humidity sensors, promising towards flexible and wearable sensing applications.