Sonication Power for Length Control of Single-Walled Carbon Nanotubes in Aqueous Suspensions Used for 2-Dimensional Network Formation

Vichchulada, Pornnipa; Cauble, Meagan A.; Абди, Э; Obi, Emmanuel I.; Zhang, Qinghui; Lay, Marcus D.

doi:10.1021/jp104102t

Cited by 63 publications

(52 citation statements)

References 39 publications

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“…The basic element is invariably a bundle rather than an individual SWNT and the use of ultrasonication to de-bundle in solution causes defectiveness and shortening [4]. Consequently there are large energy barriers at metal-semiconductor interfaces and disorder is introduced by the impurities and processing.…”

Section: Introductionmentioning

confidence: 99%

High electrical conductance enhancement in Au-nanoparticle decorated sparse single-wall carbon nanotube networks

McAndrew

Baxendale

2013

Nanotechnology

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We report high electrical conductivity enhancement in sparse single-walled carbon nanotube networks by decoration with Au nanoparticles. The optimised hybrid network exhibited a sheet resistance of 650 /sq: 1/1500 of the resistance of the host undecorated network, with a negligible optical transmission penalty (>90% transmittance at 550 nm wavelength). The electrical transport at room temperature in host and decorated networks was dominated by 2-dimensional variable range hopping.The high conductance enhancement was due to positive charge transfer from the decorating Au nanoparticles in intimate contact with the host network causing a Fermi energy shift into the high density of states at a van Hove singularity and enhanced electron delocalisation relative to the host network which beneficially modifies the hopping parameters in such a way that the network behaves as an integral whole. The effect is most pronounced when the nanoparticle diameter is comparable to the electron mean free path in the bulk material at room temperature and there is minimum nanoparticle agglomeration. For higher than optimal values of nanoparticles per unit area or nanoparticle diameter, the conductivity enhancement is countered by metallic inclusions in the current pathways that are of higher resistance than the VRH-controlled elements.

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Section: Introductionmentioning

confidence: 99%

High electrical conductance enhancement in Au-nanoparticle decorated sparse single-wall carbon nanotube networks

McAndrew

Baxendale

2013

Nanotechnology

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“…High power sonication is known to improve the dispersion of nanotubes in solutions when performed for short duration [34, 35]. However, prolonged high power sonication may shorten the length of the nanotubes and may cause defects and changes in the properties of nanotubes [36, 37]. Therefore, for the rest of the investigation, the 15 min sonicated nanotubes were used, and the MN3 column whose incorporated nanotubes were sonicated for 15 min was designated as MN3-15.…”

Section: Resultsmentioning

confidence: 99%

Facile preparation of octadecyl monoliths with incorporated carbon nanotubes and neutral monoliths with coated carbon nanotubes stationary phases for HPLC of small and large molecules by hydrophobic and π–π interactions

Mayadunne

Rassi

2014

Talanta

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Two approaches for incorporating carbon nanotubes into monolithic columns for HPLC are described in this report. They pertain to the investigation of carbon nanotubes either (i) as entities to modulate solute retention on monolithic columns bearing well defined retentive ligands or (ii) as entities that constitute the stationary phase responsible for solute retention and separation. Approach (i) involved the incorporation of carbon nanotubes into octadecyl monolithic columns while approach (ii) concerns the preparation and evaluation of an ideal monolithic support and coating it with carbon nanotubes to yield a real “carbon nanotube stationary phase” for the HPLC separation of a wide range of solutes. First, an octadecyl monolithic column based on the in situ polymerization of octadecyl acrylate and trimethylolpropane trimethacrylate was optimized for use in HPLC separations of small and large solutes (e.g., proteins). To further modulate the retention and separation of proteins, small amounts of carbon nanotubes were incorporated into the octadecyl monolith column. In approach (ii), an inert, relatively polar monolith based on the in situ polymerization of glyceryl monomethacrylate (GMM) and ethylene glycol dimethacrylate (EDMA) proved to be the most suitable support for the preparation of “carbon nanotube stationary phase”. This carbon nanotube “coated” monolith proved useful in the HPLC separation of a wide range of small solutes including enantiomers. In approach (ii), a more homogeneous incorporation of carbon nanotubes into the diol monolithic columns (i.e., GMM/EDMA) was achieved when hydroxyl functionalized carbon nanotubes were incorporated into the GMM/EDMA monolithic support. In addition, high power sonication for a short time enhanced further the homogeneity of the monolith incorporated with nanotubes. In all cases, nonpolar and π interactions were responsible for solute retention on the monolith incorporated carbon nanotubes.

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“…Because of this, minimizing the effect of those physico-chemical treatments on the CNTs characteristics becomes necessary. With regard to physical methods, sonication time, frequency and power have been proved to modify the attributes of nanotubes, such as length and hence their toxicity [16,17]. Therefore, the reduced energy delivered by sonication baths can be thought to be more appropriate than that of sonication probes.…”

Section: Acc E P Ted P R E P R I Ntmentioning

confidence: 99%

Ecotoxicity of multiwalled carbon nanotubes: Standardization of the dispersion methods and concentration measurements

Cerrillo¹,

Barandika²,

Igartua³

et al. 2015

Enviro Toxic and Chemistry

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There are currently a variety of applications for multiwalled carbon nanotubes (MWCNTs), but considerable concerns exist regarding their release into the environment. Their potential accumulation by aquatic organisms could lead to transfer throughout food chains. Considering the divergences in experimental data published on the ecotoxicity of carbon nanotubes, further research is required. The dispersion of MWCNTs in aqueous culturing media of organisms as well as the determination of concentrations are relevant aspects to obtain accurate ecotoxicity results. Ultraviolet-visible spectroscopy is one of the most reported techniques to analyze concentration quickly and economically, but the methodologies to prepare dispersions and selecting the wavelengths for ultraviolet-visible measurements have not yet been clearly defined. The present study demonstrates that dispersion procedures influence absorbance, and an approach to determine the most appropriate measurement wavelength is proposed. Ecotoxicity tests with MWCNTs were performed on Vibrio fischeri bacteria, and divergences in the results were observed with respect to those previously reported. The present study contributes to the attempt to overcome the lack of standardization in the environmental assessment of MWCNTs.

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Sonication Power for Length Control of Single-Walled Carbon Nanotubes in Aqueous Suspensions Used for 2-Dimensional Network Formation

Cited by 63 publications

References 39 publications

High electrical conductance enhancement in Au-nanoparticle decorated sparse single-wall carbon nanotube networks

High electrical conductance enhancement in Au-nanoparticle decorated sparse single-wall carbon nanotube networks

Facile preparation of octadecyl monoliths with incorporated carbon nanotubes and neutral monoliths with coated carbon nanotubes stationary phases for HPLC of small and large molecules by hydrophobic and π–π interactions

Ecotoxicity of multiwalled carbon nanotubes: Standardization of the dispersion methods and concentration measurements

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