Guar Gum/Ethyl Cellulose-Polyvinyl Pyrrolidone Composite-Based Quartz Crystal Microbalance Humidity Sensor for Human Respiration Monitoring

• Published in: ACS applied materials & interfaces Vol. 14; no. 27; pp. 31343 - 31353
• Main Authors: Yan, Weiyu, Zhang, Dongzhi, Liu, Xiaohua, Chen, Xiaoya, Yang, Chunqing, Kang, Zhanjia
• Format: Journal Article
• Language: English
• Published: American Chemical Society 13.07.2022
• Subjects: ambient temperature; Applications of Polymer, Composite, and Coating Materials; composite materials; contact angle; Fourier transform infrared spectroscopy; guar gum; humans; hydrophilicity; hysteresis; nanofibers; pyrrolidones; quartz crystal microbalance; relative humidity; X-radiation; guar gum; quartz crystal microbalance; humidity sensor; emotional breathing; electrospinning; ethyl cellulose
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.2c08434

In this work, the guar gum (GG) and the electrospinned ethyl cellulose-polyvinyl pyrrolidone (EC-PVP) nanofibers were used as humidity-sensitive materials for fabricating a quartz crystal microbalance (QCM) sensor. Fourier transform infrared spectroscopy, scanning electron microscopy, water contact angle test, and X-ray photoelectron spectra were used to characterize the synthesized GG/EC-PVP composite material, confirming its successful preparation and good hydrophilicity. The humidity sensitivity experiments were performed at room temperature. The GG/EC-PVP-coated QCM sensor has high sensitivity (55.72 Hz/%RH) and low hysteresis (2.8% RH) in a wide relative humidity range (0–97% RH), short response/recovery time (26/2 s), excellent selectivity, good repeatability, and stability. The combined action of hydrophilic groups and porous structure enhances the humidity sensitivity. The GG/EC-PVP sensor can be used to capture and measure typical breathing patterns in different human basic emotions due to its good performance. Furthermore, a lie-detector system was also designed for judging the lying through detecting the emotional breathing pattern of the subjects.