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Title: Humidity response of a capacitive sensor based on auxeticity of carbon nanotube-paper composites
Abstract Auxetic materials showing a negative Poisson’s ratio can offer unusual sensing capabilities due to drastic percolation changes. This study presents the capacitive response of wet-fractured carbon nanotube paper composites in exposure to humidity. A strained composite strip is fractured to produce numerous cantilevers consisting of cellulose fibers coated with carbon nanotubes. During stretching, the thin composite buckles in the out-of-plane direction, which causes auxetic behavior to generate the radially structured electrodes. The crossbar junctions forming among the fractured electrodes significantly increase capacitance and its response to humidity as a function of sensor widths. The molecular junctions switch electric characteristics between predominantly resistive- and capacitive elements. The resulting capacitive response is characterized for humidity sensing without the need for an additional absorption medium. The normalized capacitance change (ΔC/C 0 ) exhibits a sensitivity of 0.225 within the range of 40 ∼ 80% relative humidity. The novel auxetic behavior of a water-printed paper-based nanocomposite paves the way for inexpensive humidity and sweat sensors.  more » « less
Award ID(s):
1927623
NSF-PAR ID:
10355903
Author(s) / Creator(s):
; ; ; ; ; ;
Date Published:
Journal Name:
Nano Express
Volume:
3
Issue:
2
ISSN:
2632-959X
Page Range / eLocation ID:
025001
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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