Issue 6, 2019

A highly sensitive printed humidity sensor based on a functionalized MWCNT/HEC composite for flexible electronics application

Abstract

A novel functionalized multi-walled carbon nanotube (FMWCNT)/hydroxyethyl cellulose (HEC) composite-based humidity sensor was successfully developed for humidity monitoring applications. FMWCNTs were synthesized by covalently functionalizing multi-walled carbon nanotubes (MWCNTs) in a mixture of sulfuric and nitric acid to enhance their hydrophilicity. The FMWCNTs were characterized using transmission electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and dispersion analysis to verify the presence of functional hydroxyl and carboxyl groups. A FMWCNT/HEC (1 : 6 w/w) composite ink was formulated using the solution blending technique with 2.5 wt% FMWCNTs. A multi-layered humidity sensor was fabricated using additive print manufacturing processes on a flexible polyethylene terephthalate (PET) substrate. Screen printing and gravure printing processes were used to deposit the bottom silver (Ag) electrode and FWMCNT/HEC sensing layers, respectively. The capability of the fabricated humidity sensor was investigated by measuring its resistive response towards relative humidity (RH) varying from 20% RH to 80% RH. As the RH was increased from 20% RH to 80% RH in steps of 10% RH at 25 °C, it was observed that the resistance of the printed sensor increased linearly. The printed sensor demonstrated resistance changes as high as ≈290% at 80% RH, when compared to its base resistance at 20% RH. A sensitivity and a response time of 0.048/%RH and ≈20 s were obtained for the printed sensor, respectively. The results thus demonstrated the feasibility of employing additive print manufacturing processes to develop a highly sensitive sensor for humidity monitoring applications.

Graphical abstract: A highly sensitive printed humidity sensor based on a functionalized MWCNT/HEC composite for flexible electronics application

Supplementary files

Article information

Article type
Paper
Submitted
22 3月 2019
Accepted
12 4月 2019
First published
15 4月 2019
This article is Open Access
Creative Commons BY license

Nanoscale Adv., 2019,1, 2311-2322

A highly sensitive printed humidity sensor based on a functionalized MWCNT/HEC composite for flexible electronics application

V. S. Turkani, D. Maddipatla, B. B. Narakathu, T. S. Saeed, S. O. Obare, B. J. Bazuin and M. Z. Atashbar, Nanoscale Adv., 2019, 1, 2311 DOI: 10.1039/C9NA00179D

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