Compressive stress-electrical conductivity characteristics of multiwall carbon nanotube networks

Abstract

A network of entangled multiwall carbon nanotubes is presented as a conductor whose conductivity is sensitive to compressive stress both in the course of monotonic stress growth and when loading/unloading cycles are imposed. The testing has shown as much as 100% network conductivity increase at the maximum applied stress. It indicates favorable properties of multiwall carbon nanotube networks for their use as stress-electric signal transducers. To model the conductivity-stress dependence, it is hypothesized that compression increases local contact forces between nanotubes, which results in more conductive contacts. The lack of detailed knowledge of the mechanism as well as an unclear shift from individual contacts to the whole network conductance behavior is

A Flexible Multifunctional Sensor Based on Carbon Nanotube/Polyurethane Composite

“…The purified MWCNTs produced by chemical vapor deposition of acetylene, were supplied by Sun Nanotech Co. Ltd., China. According to the supplier, the nanotube diameter is 10-30 nm, length 1-10 μm, 90% purity and a resistivity of 0.12 Ωcm [7]. The other MWCNTs were Baytubes C70 denoted here MWCNTs (BT), produced by chemical vapor deposition and supplied by BayerMaterial Science AG, Germany (diameter 5-20 nm, length 1-10 µm, Cpurity > 99% and bulk density 140-230 kg/m 3 declared by supplier).…”

Stress-strain Hysteresis of a Carbon Nanotube Network as Polymer Nanocomposite Filler under Cyclic Deformation

“…The novel process consists of using the flexible non-woven polystyrene (PS) filter as supporting and integrating element at which, in our case, the multiwall carbon nanotubes (MWCNT) settle and form a network during MWCNT suspension filtration [5][6][7]. The obtained MWCNT/PS composite can be used either without adjustment or hot compressed to increase MWCNT fixing to PS membrane.…”

Deformation theory of an electro-conductive composite composed of entangled network of carbon nanotubes embedded in elastic polyurethane

“…The published data show that the electrical response to strain or stress is sufficient and the sensing can be performed in real time [2][3][4]. Moreover, the deformation process is reversible although some irreversibility is also measured as a hysteresis loop in cyclical loading tests [2,5,6].…”

“…The CNT based strain sensitive elements usually consist of a pure CNT entangled network of buckypaper when the resistance response to deformation is governed by nanotube interactions [1,[3][4][5][6][7][8]. The decisive role is played by local resistance in nanotube contacts and the straightening and buckling of nanotubes what affects the number of contacts between nanotubes [5].…”

“…The decisive role is played by local resistance in nanotube contacts and the straightening and buckling of nanotubes what affects the number of contacts between nanotubes [5]. Both the tensile [3,5], and compressive [1,6,7] deformation of CNT entangled network was tested. In the case of tensile load, CNT network is attached to the surface of monitored tensile specimen by epoxy resin [8], or is encapsulated into the specimen [5].…”