Highly sensitive humidity sensors based on LiCl–Pebax 2533 composite nanofibers via electrospinning

• LiCl–Pebax 2533 composite nanofibers with highly humidity sensitivity have been successfully synthesized by a simile electrospinning method.
• The impedance of the sensor changed nearly four orders of magnitude when the relative humidity changed from 11% RH to 95% RH and the hysteresis can be neglected.
• The response and recovery time of the sensor were 30 s and 80 s, respectively.

LiCl–Pebax 2533 composite nanofibers with different amounts of LiCl·H2O have been successfully synthesized by an electrospinning method. Humidity sensing properties, including the impedance versus relative humidity (RH), humidity hysteresis, and response and recovery time of these composites have been investigated. These results indicated that LiCl-added material possessed higher humidity sensitivity and LiCl–Pebax 2533 composite with LiCl·H2O content at 44.4 wt% displayed the best humidity sensing property. The impedance of the sensor changed nearly four orders of magnitude when the relative humidity changed from 11% RH to 95% RH and the hysteresis can be neglected. Furthermore, the response and recovery time of the sensor was 30 s and 80 s, respectively. Humidity sensing mechanism was analyzed by complex impedance spectra and the corresponding equivalent circuit.

The complex impedance plots of LiCl·H2O-Pebax 2533 composite with LiCl·H2O content at 44.4 wt% under different relative humidity was providedto explain the humidity sensing mechanism.Figure optionsDownload as PowerPoint slide