A novel flexible UV-cured carbon nanotube composite film for humidity sensing

A new flexible resistor-type humidity sensor was developed based on UV-cured carbon nanotube composite film as humidity-sensing material. Carbon nanotubes (CNTs) were firstly mixed with UV-curable resin via ball-milling. Simply by spin-coating of this mixture on flexible interdigitated electrode and subsequent UV-curing, a flexible humidity sensor based on UV-cured CNTs composite film was thus fabricated. With the utilization of UV-curing technology, this fabricating strategy is rather simple, highly efficient (accomplished in several minutes), cost-effective, and environmental-friendly (no organic solvent). The effect of the CNTs content, the nature of the UV-curable resin as well as their ratios on the humidity-sensing performance was systematically investigated. Under optimized conditions, the UV-cured CNTs composite film showed remarkable sensing performance over a wide humidity span from 6% to 84%. In addition, the as-prepared CNTs composite film exhibited small hysteresis and fast response. Moreover, good repeatability and long-term stability was demonstrated. This work offers a novel, economical and promising way to fabricate humidity sensors considering the facile, efficient and green preparation strategy and outstanding sensing properties.