Multi-wall carbon nanotube networks as potential resistive gas sensors for organic vapor detection

Enhancing effect of KMnO4 oxidation of carbon nanotubes network embedded in elastic polyurethane on overall electro-mechanical properties of composite

“…It indicates better nanotube dispersion in the aqueous suspension during filtration process and network formation when nanotubes are deposited individually or as a small CNT bundles. The similar finding was described in our previous paper using different kind of MWCNTs [4]. The electrical resistance of MWCNT network is mainly affected by the resistance of inter-tube contacts and the number of contacts, since the conductive nanotubes are short (max.…”

“…several micrometers) and cannot create a continuous conductive path [16,17]. However, according to our measurement, the oxidation also increases the network resistance [4].…”

“…Pristine, KMnO 4 , and oxygen plasma-oxidized MWCNTs were analyzed via transmission electron microscopy (TEM) using microscope JEOL JEM 2010 at the accelerating voltage of 160 kV. The sample for TEM was fabricated on 300 mesh copper grid with a carbon film (SPI, USA) from MWCNT dispersion in acetone prepared by ultrasonication, which was deposited on the grid and dried.…”

“…Moreover, it was found that the nanotube network made from oxidized nanotubes has 3 more uniform pore structure and dense morphology with lower porosity in comparison with networks formed by pristine nanotubes [4]. The network structure results from fine nanotube aqueous dispersion, and thus deposition of individual nanotubes and/or only small nanotube agglomerates on filtrating membrane since the presence of oxygen-containing groups facilitates the exfoliation of nanotube bundles and increases their dispersion in polar media [1,2,5].…”

A Flexible Multifunctional Sensor Based on Carbon Nanotube/Polyurethane Composite

“…The dispersion was sonicated at 40°C for an hour using UP-400S Dr. Hielsher GmbH apparatus (horn H7, amplitude 88 μm, power density 300 W/cm 3 , frequency 24 kHz) at 50% power of the apparatus and in 50% pulse mode. The product was filtered and washed with concentrated HCl to remove MnO 2 [8].…”