A study on the electrical conductivity of multi-walled carbon nanotube aqueous solution

Liu, Liyue; Yang, Yuezong; Zhang, Yafei

doi:10.1016/j.physe.2004.06.046

Cited by 42 publications

(18 citation statements)

References 11 publications

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“…The other relevant studies of CNT-based colloids did not present results for e 0 [Liu et al, 2004;Lisunova et al, 2006;Glover et al, 2008] so there is no basis for comparison of our results. However, SWCNTs are known to have high e 0 so their affect on increasing the e 0 of the colloid was expected.…”

contrasting

confidence: 56%

“…For example, the conductivity of functional sulfonated SWCNTs were evaluated in 50% deionized water/50% ethylene glycol (s ¼ 10 À3 S/m) from 100 kHz to 1 MHz [Glover et al, 2008]. The conductivity of multi-walled CNTs (MWCNTs) were evaluated in chloroform (s ¼ 2.67 Â 10 À8 S/m) and toluene (s ¼ 3.4 Â 10 À10 S/m) at DC [Liu et al, 2004], and in 0.01 M KCl (s ¼ 0.12 S/m) with Triton X-305 surfactant at 1 kHz [Lisunova et al, 2006]. The relative effect of conductive nanoparticles on the aggregate colloid s (and relative SAR) is predicted to be significantly larger in solvents that are intrinsically poor conductors like deionized water (s $ 10 À5 S/m) or organic solvents, compared to biologically compatible electrolyte solutions (s > 0.2 S/m).…”

Section: Introductionmentioning

confidence: 99%

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Radiofrequency interaction with conductive colloids: Permittivity and electrical conductivity of single‐wall carbon nanotubes in saline

Gach

Nair²

2010

Bioelectromagnetics

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Conductive nanoparticles may enhance tissue heating during radiofrequency (RF) irradiation. Specific absorption rate (SAR) is known to rise with the electrical conductivity of tissue. However, no studies to date have measured the relationship between complex permittivity and nanoparticle concentration in tissue-like samples. The complex permittivities of colloids containing single-wall carbon nanotubes (SWCNTs) in normal (0.9%) saline were measured from 20 MHz to 1 GHz. Carbon concentrations ranged from 0 to 93 mM (0.06% volume), based on SWCNT weight per volume. Measurements were made with 0.02% Pluronic F108 surfactant added to the colloids to prevent SWCNT flocculation. The data were fit to the Cole-Cole relaxation model with an added constant phase angle element to correct for electrode polarization effects at low RF frequencies. Electrode polarization effects increased with carbon concentration. The real parts of the permittivities of the colloids increased with carbon concentration. The static conductivity rose linearly with carbon concentration, doubling from 0 to 93 mM. The SAR of the colloids is expected to increase with RF frequency, based on the properties of the imaginary part of the permittivity.

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contrasting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Radiofrequency interaction with conductive colloids: Permittivity and electrical conductivity of single‐wall carbon nanotubes in saline

Gach

Nair²

2010

Bioelectromagnetics

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“…Unlike the documented oriented nanofibers (Ra et al, 2005), herein, the deposited nanofibers on the collector were isotropic, as shown in Figure 1b. However, MWCNTs could align along the single nanofiber, not only due to the ejecting stress (Cooper et al, 2002;Haggenmueller et al, 2000) at the spinneret, but also the present high electric field (Liu et al, 2004;Takahashi et al, 2006). Typical SEM images in Figure 2a-d show the surface morphologies of the electrospun nanofiber mesh with different MWCNTs concentrations.…”

Section: Storage Stabilities Of the Free And Immobilized Catalasesmentioning

confidence: 99%

“…The carboxyl groups on the etched MWCNTs surfaces could interact with DMF and ÀCOOH (through hydrogen bond) in PANCAA, which increased the solution viscosity (Fig. 2f), and the enhanced electrical conductivity was ascribed to MWCNTs addition to the polymer solution (Liu et al, 2004). The competition between the solution viscosity and the electrical conductivity resulted in the biggest average diameter of the nanofiber.…”

Section: Storage Stabilities Of the Free And Immobilized Catalasesmentioning

confidence: 99%

“…The reaction takes place in two-electron reactions with the first hydrogen peroxide molecule oxidizing the heme to compound I, generating the oxoferryl species and a porphyrin cation radical (Reaction 1). Then, two electrons transfer from the second hydrogen peroxide to regenerate the resting enzyme while releasing water and oxygen molecules (Reaction 2) (Liu et al, 2004). Reaction 1, in which H 2 O 2 serves as H donor for Cpd I, proceeds exceedingly rapidly and peroxidative reaction proceeds relatively slow.…”

Section: Storage Stabilities Of the Free And Immobilized Catalasesmentioning

confidence: 99%

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Covalent immobilization of redox enzyme on electrospun nonwoven poly(acrylonitrile‐co‐acrylic acid) nanofiber mesh filled with carbon nanotubes: A comprehensive study

Wang

2007

Biotech & Bioengineering

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In this work, novel conductive composite nanofiber mesh possessing reactive groups was electrospun from solutions containing poly(acrylonitrile-co-acrylic acid) (PANCAA) and multi-walled carbon nanotubes (MWCNTs) for redoxase immobilization, assuming that the incorporated MWCNTs could behave as electrons transferor during enzyme catalysis. The covalent immobilization of catalase from bovine liver on the neat PANCAA nanofiber mesh or the composite one was processed in the presence of EDC/NHS. Results indicated that both the amount and activity retention of bound catalase on the composite nanofiber mesh were higher than those on the neat PANCAA nanofiber mesh, and the activity increased up to 42%. Kinetic parameters, K(m) and V(max), for the catalases immobilized on the composite nanofiber mesh were lower and higher than those on the neat one, respectively. This enhanced activity might be ascribed to either promoted electron transfer through charge-transfer complexes and the pi system of carbon nanotubes or rendered biocompatibility by modified MWCNTs. Furthermore, the immobilized catalases revealed much more stability after MWCNTs were incorporated into the polymer nanofiber mesh. However, there was no significant difference in optimum pH value and temperature, thermal stability and operational stability between these two immobilized preparations, while the two ones appeared more advantageous than the free in these properties. The effect of MWCNTs incorporation on another redox enzyme, peroxidase, was also studied and it was found that the activity increased by 68% in comparison of composite one with neat preparation.

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Swelling, pH sensitivity, and mechanical properties of poly(acrylamide‐co‐sodium methacrylate) nanocomposite hydrogels impregnated with carboxyl‐functionalized carbon nanotubes

Yang

Luo

2012

Polymer Composites

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A series of novel nanocomposite hydrogels were prepared by a cross‐linking copolymerization method. Structural and morphological characterizations of the nanocomposite hydrogels revealed that a good compatibility exists between poly(acrylamide‐co‐sodium methacrylate) [P(AM‐co‐SMA)] and carboxyl‐functionalized carbon nanotubes (MWNTs–COOH). The P(AM‐co‐SMA)/MWNTs–COOH nanocomposite hydrogels with a suitable MWNTs–COOH loading exhibited better swelling capability, higher pH sensitivity, good reversibility, and repeatability, and rapid response to external pH stimuli, compared with the P(AM‐co‐SMA). The compression mechanical tests revealed that the nanocomposite hydrogel displayed excellent compressive strengths and elastic mechanical properties, with higher ultimate compressive stress, and meanwhile still retain a good recoverable strain in the presence of MWNTs–COOH. These excellent properties may primarily be attributed to effectively dispersing of a suitable MWNTs–COOH loading into the matrix of the polymers and formation of additional hydrogen bonds. The nanocomposite hydrogels were expected to find applications in drug controlled release and issue engineering. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

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A study on the electrical conductivity of multi-walled carbon nanotube aqueous solution

Cited by 42 publications

References 11 publications

Radiofrequency interaction with conductive colloids: Permittivity and electrical conductivity of single‐wall carbon nanotubes in saline

Radiofrequency interaction with conductive colloids: Permittivity and electrical conductivity of single‐wall carbon nanotubes in saline

Covalent immobilization of redox enzyme on electrospun nonwoven poly(acrylonitrile‐co‐acrylic acid) nanofiber mesh filled with carbon nanotubes: A comprehensive study

Swelling, pH sensitivity, and mechanical properties of poly(acrylamide‐co‐sodium methacrylate) nanocomposite hydrogels impregnated with carboxyl‐functionalized carbon nanotubes

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