Fabrication of a novel sensor based on ionic porous polymer microspheres for humidity monitoring

• Published in: Sensors and actuators. B, Chemical Vol. 422; p. 136638
• Main Authors: Zhang, Ying, Wang, Shanshan, Ha, Fugui, Fu, Yu, Jia, Qin-Xiang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2025
• Subjects: Humidity sensor; Ionic porous polymer; Microspheres; Sensing mechanism; Humidity sensor; Ionic porous polymer; Microspheres; Sensing mechanism
• ISSN: 0925-4005
• DOI: 10.1016/j.snb.2024.136638

A novel humidity sensor based on ionic porous polymer (IPP) microspheres was prepared in this work. The chemical structure and morphology of IPP microspheres were carefully characterized. The intrinsic hydrophilic ionic units of IPP, –N+R– and Br–, could enhance the adsorption of water molecules and ionic conductivity. The aromatic groups in IPP can adjust its hydrophobicity and ensure stability. Meanwhile, the structure of microspheres provides a favorable space of channels for water molecules transport, which improves the response speed of sensing film further. The impedance of the sensor based on IPP microspheres changed more than three orders of magnitude in the relative humidity (RH) range of 11–95 % RH with a good linearity (R2=0.996) and a fast response speed (6 s/ 27 s). Finally, the mechanism was systematically studied by complex impedance spectrum and theoretical calculation. This study shows a new type of sensor based on ionic porous polymer microspheres, which will pave the way for IPP applications in humidity sensing. •Ionic porous polymer microspheres were successfully fabricated into the humidity sensor.•The sensor exhibits good linearity, rapid response speed and excellent stability.•Sensing mechanism was analyzed by the CIS, EC and theoretical calculation.