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

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.

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.605.322 ◽

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.

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Application of Plasma Modified Multiwall Carbon Nanotubes to Ethanol Vapor Detection

ECS Meeting Abstracts ◽

10.1149/ma2010-02/1/30 ◽

2010 ◽

Keyword(s):

Carbon Nanotubes ◽

Multiwall Carbon Nanotubes ◽

Ethanol Vapor ◽

Vapor Detection ◽

Multiwall Carbon

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.495.9 ◽

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.

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Electric Field Effects on Self-Organization Processes during Droplet Evaporation of Multiwall Carbon Nanotube Aqueous Suspension

Materials Science Forum ◽

10.4028/www.scientific.net/msf.936.25 ◽

2018 ◽

Vol 936 ◽

pp. 25-30

Author(s):

A.P. Kuzmenko ◽

N.A. Khokhlov ◽

Thet Phyo Naing ◽

Myo Min Than

Keyword(s):

Carbon Nanotubes ◽

Electric Field ◽

Aqueous Suspension ◽

Multiwall Carbon Nanotubes ◽

Droplet Evaporation ◽

Self Organization ◽

Uniform Electric Field ◽

Multiwall Carbon Nanotube ◽

Walled Carbon Nanotubes ◽

Multiwall Carbon

The self-organization of COOH-functionalized multiwall carbon nanotubes (MWCNTs) during droplet evaporation of their aqueous suspension in a constant uniform electric field (E) was investigated. It was established that the COOH-functionalization polarizes the MWCNTs in the transverse direction to their axis. Depending on their size, MWCNTs tended to agglomerate into three different stable structures in different drop regions. There were linear, fractal and cluster structures (LS, FS, and CS). Sizes of the FSs decreased as 1/Е, whereas the rate of their growth increased as Е2. The single-walled carbon nanotubes (SWCNTs) were found inside the LSs and CSs. The chiral indices of the SWCNTs were determined, corresponding to metallic and semiconducting conductivities. An analysis showed that as a result of coagulation and amassment of the carbon nanotubes (CNTs) near electrodes, there were formed conductive regions. When the concentration of MWCNTs reached some value in part nearest to an electrode, this part became conductive. The positive and negative electrodes, formed now by MWCNTs, shifted towards each other. The observed effects show that considered self-organization is controllable by the electric field.

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TUNING THE OPTICAL PROPERTIES OF MULTIWALL CARBON NANOTUBE THIN FILMS BY N+ ION BEAMS IRRADIATION

NANO ◽

10.1142/s179329201100269x ◽

2011 ◽

Vol 06 (04) ◽

pp. 357-362 ◽

Cited By ~ 9

Author(s):

AHMAD ISHAQ ◽

LONG YAN ◽

G. HUSNAIN ◽

BO LU ◽

MAHMOOD ARSHAD ◽

...

Keyword(s):

Thin Films ◽

Optical Transmission ◽

Structural Changes ◽

Multiwall Carbon Nanotubes ◽

Ion Beams ◽

Visible Spectral Range ◽

Multiwall Carbon Nanotube ◽

Filtration Method ◽

Vacuum Filtration ◽

Multiwall Carbon

Measurements of optical transmission in the visible spectral range of N+ irradiated thin films of multiwall carbon nanotubes (MWCNTs) at various doses prepared by a vacuum filtration method are reported. An increase in optical transmission was observed corresponding to increase in N+ ion doses. Changes in Raman spectra at different ions doses ranging from 5 × 1015 ions/cm2 to 1 × 1017 ions/cm2 indicate that the structure of graphene evolves from a highly ordered layer to a disordered domains. These structural changes result in a dramatic increase in the optical transmission. Additionally, the increase of optical transmission of irradiated MWCNTs thin film as a function of electrical conductivity at various doses is also discussed. The optical transmission increases in irradiated MWCNT thin films is found to be a function of defects density in MWCNTs.

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.495.355 ◽

2011 ◽

Vol 495 ◽

pp. 355-358 ◽

Cited By ~ 1

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

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Plain para-aramid/phenolic multiwall carbon nanotubes prepreg/multistiched preform composites: Experimental characterization of mode-I toughness

Journal of Composite Materials ◽

10.1177/0021998318812176 ◽

2018 ◽

Vol 53 (13) ◽

pp. 1847-1864 ◽

Cited By ~ 3

Author(s):

K Bilisik ◽

E Sapanci

Keyword(s):

Fracture Toughness ◽

Multiwall Carbon Nanotubes ◽

Beam Theory ◽

Mode I ◽

Multiwall Carbon Nanotube ◽

Axial Filament ◽

Pull Out ◽

Fiber Bridging ◽

Nanotube Composites ◽

Multiwall Carbon

The fracture toughness (mode-I) properties of nanostitched para-aramid/phenolic multiwall carbon nanotube prepreg composites were investigated. The fracture toughness (GIC) of the stitching and nanostitched composites showed 42-fold and 41-fold (beam theory), 18-fold and 21-fold (modified beam theory) increase compared to the control, respectively. The prepreg para-aramid stitching yarn and nanostitched yarn were dominant parameters. The toughness resistance to arrest crack growth in the nanostitched composite was primarily due to nanostitching fiber bridging and pull-out, and was secondarily due to nanotubes and biaxial fiber bridging and pull-out. The failed surfaces of the nanostitched and stitching composites had tensile filament failures in the aramid stitching fibers where filament/matrix/nanotube debonding and axial filament fibrillar splitting were found. The results indicated that stitching yarn and the nanotubes arrested the crack propagation. Therefore, the nanostitched and stitched para-aramid/phenolic composites displayed a better damage resistance performance compared to those of the control or nanotube composites.

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Electroless Coating of Silver on Multiwall Carbon Nanotubes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.710.774 ◽

2012 ◽

Vol 710 ◽

pp. 774-779

Author(s):

Niraj Nayan ◽

S.V.S. Narayana Murty ◽

S.C. Sharma ◽

K. Sreekumar ◽

Parameshwar Prasad Sinha

Keyword(s):

Carbon Nanotubes ◽

Surface Modification ◽

Multiwall Carbon Nanotubes ◽

Activation Process ◽

Multiwall Carbon Nanotube ◽

Effective Utilization ◽

Electroless Coating ◽

Silver Matrix ◽

Electrical Brush ◽

Multiwall Carbon

Silver reinforced with carbon nanotubes, instead of graphite, would increase both the electrical conductivity, hardness and wear resistance of the electrical brush materials. The effective utilization of carbon nanotubes in the Ag/CNT composite depends strongly on its uniform distribution and strong interfacial adhesion to the silver matrix and thus demands for its surface modification. In order to carry out the surface modification of carbon nanotubes, electroless coating was given to them after liquid phase oxidation, sensitization and activation process. The room-temperature chemical treatment results in a nominally complete coating over the entire outer surface of multiwall carbon nanotube. The surface morphology of the carbon nanotubes after each step has been studied using TGA, DSC, XRD, FTIR and SEM.

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Multiwall Carbon Nanotube-Induced Apoptosis and Antioxidant Gene Expression in the Gills, Liver, and Intestine ofOryzias latipes

BioMed Research International ◽

10.1155/2015/485343 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Jin Wuk Lee ◽

Young Chul Choi ◽

Rosa Kim ◽

Sung Kyu Lee

Keyword(s):

Gene Expression ◽

Multiwall Carbon Nanotubes ◽

Gene Induction ◽

Multiwall Carbon Nanotube ◽

Antioxidant Gene ◽

Significant Gene ◽

Antioxidant Gene Expression ◽

And Gender ◽

Induced Apoptosis ◽

Multiwall Carbon

Multiwall carbon nanotubes (MWCNTs) have many attractive properties with potential applications in various fields. Despite their usefulness, however, the associated waste can be hazardous to the environment. To examine adverse effects in aquatic environments,Oryzias latipeswere exposed to MWCNTs dispersed in water for 14 days and apoptosis and antioxidant gene expression were observed. This work showed that in gills exposed to 100 mg/L MWCNTs for 4 days, there was significantp53,caspase-3 (Cas3),caspase-8 (Cas8), andcaspase-9 (Cas9)gene expression relative to the controls, whilecatalase (CAT)andglutathione-S-transferase (GST)expression were reduced. At 14 days,CAT,GST, andmetallothionein (MT)were induced significantly in the gills andCas3,Cas8, andCas9were induced in the liver. No significant gene induction was seen in intestine. Intracellular reactive oxygen species (ROS) were increased significantly only at 14 days. Histologically, no apoptosis was observed with exposure to 100 mg/L MWCNTs for 21 days. The gills were more sensitive to MWCNT toxicity than the other organs. Males had higher apoptosis gene induction than females. These results demonstrated that MWCNTs could cause apoptosis in a manner influenced by tissue and gender in aqueous environments.

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Highly Deformable Porous Electromagnetic Wave Absorber Based on Ethylene–Propylene–Diene Monomer/Multiwall Carbon Nanotube Nanocomposites

Polymers ◽

10.3390/polym12040858 ◽

2020 ◽

Vol 12 (4) ◽

pp. 858 ◽

Cited By ~ 1

Author(s):

Hasti Bizhani ◽

Ali Asghar Katbab ◽

Emil Lopez-Hernandez ◽

Jose Miguel Miranda ◽

Raquel Verdejo

Keyword(s):

Electromagnetic Interference ◽

Multiwall Carbon Nanotubes ◽

Multiwall Carbon Nanotube ◽

Ethylene Propylene Diene Monomer ◽

Ethylene Propylene ◽

Electrical Percolation ◽

Vulcanized Rubber ◽

Electrical Percolation Threshold ◽

High Flexibility ◽

Multiwall Carbon

The need for electromagnetic interference (EMI) shields has risen over the years as the result of our digitally and highly connected lifestyle. This work reports on the development of one such shield based on vulcanized rubber foams. Nanocomposites of ethylene–propylene–diene monomer (EPDM) rubber and multiwall carbon nanotubes (MWCNTs) were prepared via hot compression molding using a chemical blowing agent as foaming agent. MWCNTs accelerated the cure and led to high shear-thinning behavior, indicative of the formation of a 3D interconnected physical network. Foamed nanocomposites exhibited lower electrical percolation threshold than their solid counterparts. Above percolation, foamed nanocomposites displayed EMI absorption values of 28–45 dB in the frequency range of the X-band. The total EMI shielding efficiency of the foams was insignificantly affected by repeated bending with high recovery behavior. Our results highlight the potential of cross-linked EPDM/MWCNT foams as a lightweight EM wave absorber with high flexibility and deformability.

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