PVA/Tween 20 thin-film-based fiber optic humidity sensor with enhanced sensing performance.

A fiber optic humidity sensor based on polyvinyl alcohol (PVA)/Tween 20 film has been fabricated by modulating the intensity of light transmitted in optical fiber. PVA/Tween 20 film was used as the cladding and humidity-sensitive material of optical fiber. The logarithmic of output light intensity exhibited a linear increase with the increase of humidity (22%-82%RH). With the addition of Tween 20 in the formation of film, average sensitivity increased by 13-fold. Fast equilibrium on adsorption and desorption of water molecules were also achieved on the film. The response and recovery times were determined to be 11 s and 9 s, respectively. Moreover, the sensor possesses good repeatability. The sensing mechanism was probably based on the swelling of PVA after adsorbing water molecules, which affected scattering of evanescent waves in the cladding. The output light intensity varied with the decay of evanescent waves.

Citation

Ziming Zhao, Min Lai, Yang Yang, Jinze Li, Huatang Song, Jixiang He, Hengheng Zhang, Yaya Mao, Yan Ma, Bo Liu. PVA/Tween 20 thin-film-based fiber optic humidity sensor with enhanced sensing performance. Applied optics. 2022 Mar 01;61(7):1834-1840

PMID: 35297866

search → result