The Multifunctional Composite on the Base of Carbon Nanotubes Network and its Use as a Passive Antenna and Gas Sensing Element

2014 ◽  
Vol 605 ◽  
pp. 322-325
Author(s):  
Robert Olejnik ◽  
Jiri Matyas ◽  
Petr Slobodian ◽  
Karel Vlcek
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensing ◽  
Aqueous Suspension ◽  
Multiwall Carbon Nanotubes ◽  
Sensing Element ◽  
Vapor Detection ◽  
Filtration Method ◽  
Wide Range ◽  
Passive Antenna ◽  
Nonpolar Organic

Carbon nanotubes in the form of entangled network can be used as a multifunctional composite material for a wide range of using. A new and perspective usage is a passive antenna and gas sensing element. The antenna works well at 1.284 GHz. The local reflection minimum is 11.48 dB. The reflection coefficient r=0.2667. The transmission power in this frequency is 93%. Multiwall carbon nanotubes (MWCNT) network Buckypaper was made by the vacuum filtration method of MWCNT aqueous suspension. The sensitivity of multi-wall carbon nanotube (MWCNT) networks of randomly entangled pure and HNO3 oxidized nanotubes to polar and nonpolar organic vapors (ethanol, heptane), has been investigated by resistance measurements. The results demonstrate that the network electrical resistance increases when exposed to organic solvent vapors, and a reversible reaction is observed when the sample is removed from the vapors. The investigated MWCNT networks could be potentially used as sensing elements for sensitive and selective organic vapor detection.

Sensing Element Made of Multi-Wall Carbon Nanotube Network for Organic Vapor Detection

2011 ◽  
Vol 495 ◽  
pp. 9-12
Author(s):  
Robert Olejnik ◽  
Petr Slobodian ◽  
Petr Saha
Keyword(s):  
Carbon Nanotube ◽  
Organic Solvent ◽  
Aqueous Suspension ◽  
Multiwall Carbon Nanotubes ◽  
Sensing Element ◽  
Vapor Detection ◽  
Filtration Method ◽  
Organic Vapor ◽  
Multi Wall Carbon Nanotube ◽  
Solvent Vapors

Multiwall carbon nanotubes (MWCNT) network “Buckypaper” was made by the vacuum filtration method of MWCNT aqueous suspension. The sensitivity of multi-wall carbon nanotube (MWCNT) networks of randomly entangled pure nanotubes to various organic solvent vapors (tetrahydrofuran, methyl ethyl ketone, and ethanol) has been investigated by resistance measurements. The results demonstrate that the network electrical resistance increases when exposed to organic solvent vapors, and a reversible reaction is observed when the sample is removed from the vapors. The investigated MWCNT networks could be potentially used as sensing elements for sensitive and selective organic vapor detection.

Sensing Element Made of Multi-Wall Carbon Nanotube Network for Organic Vapor Detection

2011 ◽  
Vol 495 ◽  
pp. 355-358 ◽  
Author(s):  
Robert Olejnik ◽  
Petr Slobodian ◽  
Petr Saha
Keyword(s):  
Carbon Nanotube ◽  
Organic Solvent ◽  
Aqueous Suspension ◽  
Multiwall Carbon Nanotubes ◽  
Sensing Element ◽  
Vapor Detection ◽  
Filtration Method ◽  
Organic Vapor ◽  
Multi Wall Carbon Nanotube ◽  
Solvent Vapors

Multiwall carbon nanotubes (MWCNT) network “Buckypaper” was made by the vacuum filtration method of MWCNT aqueous suspension. The sensitivity of multi-wall carbon nanotube (MWCNT) networks of randomly entangled pure nanotubes to various organic solvent vapors (tetrahydrofuran, methyl ethyl ketone, and ethanol) has been investigated by resistance measurements. The results demonstrate that the network electrical resistance increases when exposed to organic solvent vapors, and a reversible reaction is observed when the sample is removed from the vapors. The investigated MWCNT networks could be potentially used as sensing elements for sensitive and selective organic vapor detection.

Improved Selectivity of Oxidized Multiwall Carbon Nanotube Network for Detection of Ethanol Vapor

2011 ◽  
Vol 495 ◽  
pp. 83-86 ◽  
Author(s):  
Daniel Matejik ◽  
Robert Olejnik ◽  
Petr Slobodian ◽  
Petr Saha
Keyword(s):  
Aqueous Suspension ◽  
Multiwall Carbon Nanotubes ◽  
Ethanol Vapor ◽  
Solubility Parameters ◽  
Multiwall Carbon Nanotube ◽  
Hansen Solubility Parameters ◽  
Vapor Detection ◽  
Filtration Method ◽  
Carbon Nanotube Network ◽  
Multiwall Carbon

Two kinds of Multiwall carbon nanotubes (MWCNT) networks “Buckypaper” were made by the vacuum filtration method of MWCNT aqueous suspension. The first one was prepared from pure CNT and the second from its oxidized form by acidic KMnO4 as oxidizing agent. The CNT oxidation increase content of oxygen bonded to the surface of CNT decreasing their hydrophobic character. The sensitivity of MWCNT networks to two kind of organic solvent vapors (ethanol and hepane) has been investigated by resistance measurements. The solvents had different polarities given by Hansen solubility parameters and nearly the same volume fractions of saturated vapors at the condition of experiment. CNT oxidation significantly increases the sensitivity of CNT resistive sensor to vapors of ethanol and decrease response to heptane vapors. The present paper demonstrates the effective way how to add proper selectivity for organic vapor detection.

scholarly journals Gas sensing properties of multiwall carbon nanotubes decorated with rhodium nanoparticles

2011 ◽  
Vol 160 (1) ◽  
pp. 974-980 ◽  
Author(s):  
R. Leghrib ◽  
T. Dufour ◽  
F. Demoisson ◽  
N. Claessens ◽  
F. Reniers ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensing ◽  
Multiwall Carbon Nanotubes ◽  
Sensing Properties ◽  
Rhodium Nanoparticles ◽  
Gas Sensing Properties ◽  
Multiwall Carbon

scholarly journals Incorporation of Functionalized Multiwall Carbon Nanotubes into a Polyurethane Matrix

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Martin Michálek ◽  
Michael Bredol
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Percolation Threshold ◽  
Aqueous Suspension ◽  
Sodium Dodecyl ◽  
Multiwall Carbon Nanotubes ◽  
Glass Substrates ◽  
Functionalized Mwcnts ◽  
Multiwall Carbon

Functionalized and raw multiwall carbon nanotubes (MWCNTs) were investigated colloid-chemically in order to study the role of polar versus nonpolar interaction with a polyurethane (PU) matrix. Both kinds of MWCNTs were dispersed by ultrasonication in the presence of a surfactant (sodium dodecyl sulphate) in aqueous solution. Functional groups on the nanotube surface were characterized by infrared spectroscopy and by theζ-potential in aqueous suspension. Such suspensions were added to waterborne PU dispersions, drop-cast on glass substrates and cured. The percolation threshold for electrical conductivity with polar (functionalized) MWCNTs was reached at 0.24 wt.%, whereas at concentrations as high as 2 wt.%, PU films with nonpolar MWCNTs stayed below the percolation threshold. With an addition of 0.4 wt.% polar MWCNTs, the electrical conductivity increased to >10−6 S/cm in the cured coating layer. These results are interpreted with respect to the chemical nature of the PU matrix.

Plasma Treatment as a Way of Increasing the Selectivity of Carbon Nanotube Networks for Organic Vapor Sensing Elements

2013 ◽  
Vol 543 ◽  
pp. 410-413
Author(s):  
Robert Olejnik ◽  
Petr Slobodian ◽  
Uros Cvelbar ◽  
Pavel Riha ◽  
Petr Sáha
Keyword(s):  
Carbon Nanotubes ◽  
Plasma Treatment ◽  
Electrical Resistance ◽  
Gas Sensing ◽  
Rf Plasma ◽  
Vapor Detection ◽  
Organic Vapor ◽  
Vapor Sensing ◽  
Multi Walled Carbon Nanotubes ◽  
Carbon Nanotubes Networks

Multi-walled carbon nanotubes networks (MWCNTs) were used as a layer for organic vapor detection. The sensor detects volatile organic compounds (VOC). The gas sensing by MWCNTs is measured by means of macroscopic electrical resistance. The selected solvents had different polarities and volume fractions of saturated vapors. The electrical resistance of MWCNTs increases when exposed to organic solvent vapors, and a reversible reaction is observed when the MWCNT is removed from the vapors. The MWCNTs were modified by means of plasma treatment. For modifications RF plasma in O2 at 50 Pa and an afterglow configuration were used. The modified MWCNTs show an increase in sensitivity caused by creating carboxylic groups on the surface of the carbon nanotubes. It leads, for example, to enhancement of the sensitivity from usual 30 % for heptane at RT to more than 200% after plasma treatment in O2 for 10s.

Multiwall Carbon Nanotubes Decorated with Metal Oxide Nanoparticles for Gas Sensing Applications

2019 ◽  
Vol 23 (1) ◽  
pp. 237-242 ◽  
Author(s):  
Rogerio V. Gelamo ◽  
Ali Abbaspourrad ◽  
C. Verissimoa ◽  
Alfredo R. Vaz ◽  
F. P. Rouxinol ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Metal Oxide ◽  
Gas Sensing ◽  
Metal Oxide Nanoparticles ◽  
Multiwall Carbon Nanotubes ◽  
Oxide Nanoparticles ◽  
Sensing Applications ◽  
Multiwall Carbon

scholarly journals Thermoplastic polyurethane flexible capacitive proximity sensor reinforced by CNTs for applications in the creative industries

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reza Moheimani ◽  
Nojan Aliahmad ◽  
Nahal Aliheidari ◽  
Mangilal Agarwal ◽  
Hamid Dalir
Keyword(s):  
Carbon Nanotubes ◽  
Thermoplastic Polyurethane ◽  
Creative Industries ◽  
Detection Accuracy ◽  
Sensing Element ◽  
Detection Distance ◽  
Proximity Sensor ◽  
Capacitance Effect ◽  
Wide Range ◽  
And Performance

AbstractWearable sensing platforms have been rapidly advanced over recent years, thanks to numerous achievements in a variety of sensor fabrication techniques. However, the development of a flexible proximity sensor that can perform in a large range of object mobility remains a challenge. Here, a polymer-based sensor that utilizes a nanostructure composite as the sensing element has been presented for forthcoming usage in healthcare and automotive applications. Thermoplastic Polyurethane (TPU)/Carbon Nanotubes (CNTs) composites are capable of detecting presence of an external object in a wide range of distance. The proximity sensor exhibits an unprecedented detection distance of 120 mm with a resolution of 0.3%/mm. The architecture and manufacturing procedures of TPU/CNTs sensor are straightforward and performance of the proximity sensor shows robustness to reproducibility as well as excellent electrical and mechanical flexibility under different bending radii and over hundreds of bending cycles with variation of 4.7% and 4.2%, respectively. Tunneling and fringing effects are addressed as the sensing mechanism to explain significant capacitance changes. Percolation threshold analysis of different TPU/CNT contents indicated that nanocomposites having 2 wt% carbon nanotubes are exhibiting excellent sensing capabilities to achieve maximum detection accuracy and least noise among others. Fringing capacitance effect of the structure has been systematically analyzed by ANSYS Maxwell (Ansoft) simulation, as the experiments precisely supports the sensitivity trend in simulation. Our results introduce a new mainstream platform to realize an ultrasensitive perception of objects, presenting a promising prototype for application in wearable proximity sensors for motion analysis and artificial electronic skin.

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