Highly Sensitive Humidity Sensors Based on Polyethylene Oxide/CuO/Multi Walled Carbon Nanotubes Composite Nanofibers

Abstract

Polymer composites are favorite materials for sensing applications due to their low cost and easy fabrication. In the current study, composite nanofibers consisting of polyethylene oxide (PEO), oxidized multi-walled carbon nanotubes (MWCNT) and copper oxide (CuO) nanoparticles with 1% and 3% of fillers (i.e., PEO–CuO–MWCNT: 1%, and PEO–CuO–MWCNT: 3%) were successfully developed through electrospinning for humidity sensing applications. The composite nanofibers were characterized by FTIR, XRD, SEM and EDX analysis. Firstly, they were loaded on an interdigitated electrode (IDE), and then the humidity sensing efficiency was investigated through a digital LCR meter (E4980) at different frequencies (100 Hz–1MHz), as well as the percentage of relative humidity (RH). The results indicated that the composite nanofibers containing 1% and 3% MWCNT, combined with CuO in PEO polymer matrix, showed potent resistive and capacitive response along with high sensitivity to humidity at room temperature in an RH range of 30–90%. More specifically, the PEO–CuO–MWCNT: 1% nanocomposite displayed a resistive rapid response time within 3 s and a long recovery time of 22 s, while the PEO–CuO–MWCNT: 3% one exhibited 20 s and 11 s between the same RH range, respectively.

MEMS Humidity Sensors

“…Metal-Organic Framework (MOF) thin film-coated metal oxide layers have recently been exploited to implement ultra-high sensitivity gas sensors. A thin MOF layer is gradually coated on the ZnO surface to form an ultrahigh sensitive layer to further tune the newly integrated MOF and ZnO materials with desired properties to detect gas and humidity efficiently [20][21][22]. The piezoelectric sensor can be used in sensing applications based on the changes in the physical properties of the device, such as stress or the mass due to gas absorption at the surface of the device.…”

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A resistive sensor for humidity detection based on cellulose/polyaniline

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