Quantitative assessment of carbon nanotube dispersions by Raman spectroscopy

Salzmann, Christoph G.; Chu, Bryan; Tobias, Gerard; Llewellyn, Simon A.; Green, Malcolm L. H.

doi:10.1016/j.carbon.2007.01.009

Cited by 63 publications

(55 citation statements)

References 32 publications

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“…Peak intensities in Raman spectroscopy are proportional to the MWCNT concentration. Increases in the intensity and area of the G-, G¢-and D-band peaks could be seen with increases in the concentration of MWCNT, which is consistent with the results reported by Salzmann et al 36 Similarly, the PVDF band peak area decreased with an increase in MWCNT concentration. In Raman line mapping (Figures 9c, d, e and f), a multispectrum file is acquired.…”

Section: Piezoresponse Of Pvdf-mwcnt Composites S Vidhate Et Alsupporting

confidence: 91%

Resistive–conductive transitions in the time-dependent piezoresponse of PVDF-MWCNT nanocomposites

Vidhate

Chung²,

Vaidyanathan

et al. 2010

Polym J

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Nanocomposites were prepared by melt blending of multiwalled carbon nanotubes (MWCNTs) filled with polyvinylidene fluoride. Time-dependent piezoresistance was investigated as a function of concentration. In the quasi-static case, a transition from negative pressure coefficient to positive pressure coefficient (PPC) behavior was observed. The PPC effect was negligible at high concentrations. At short times, the resistive response decreased for all nanocomposites, with the magnitude of the decrease proportionate to the MWCNT concentration. However, long-term creep response was resistive for low concentrations and conductive at high concentrations. A Burgers model based on Maxwell and Kelvin elements in series was used to describe the strain dependence. An equivalent model that uses resistances and capacitances was examined for the time dependence of fractional resisitivity. Results were correlated with Raman mapping-based dispersion analysis. An increased dispersion and an increase in MWCNT-MWCNT contact area resulted in a transition from a matrix-based resistive response to a filler-based conductive response.

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Section: Piezoresponse Of Pvdf-mwcnt Composites S Vidhate Et Alsupporting

confidence: 91%

Resistive–conductive transitions in the time-dependent piezoresponse of PVDF-MWCNT nanocomposites

Vidhate

Chung²,

Vaidyanathan

et al. 2010

Polym J

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“…Raman spectroscopy is a powerful tool for characterizing functionalized carbon nanomaterials: [80,81] spectra shown in were recorded for dispersed samples deposited from CHCl 3 :EtOH (4:1) or DMSO using λ ex = 830 nm, i.e. a region of the emission spectra of the NDI@SWNT without interference from fluorescence emission from NDI.…”

Section: Spectroscopic Investigations On the Ndi@swnt Compositementioning

confidence: 99%

Interactions Between Amino Acid‐Tagged Naphthalenediimide and Single Walled Carbon Nanotubes for the Design and Construction of New Bioimaging Probes

Pantoş

Kuganathan

et al. 2011

Adv Funct Materials

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A new synthetic route to functionalized single walled carbon nanotubes (SWNTs) via supramolecular interactions using a specifically designed naphthalenediimide (NDI) nanoreceptor is demonstrated. The tendency of the NDI to spontaneously form composites with carbon nanomaterials leads to fluorescent amino acid tagged SWNTs, which are dispersible in widely accessible organic solvents (CHCl 3 , DMSO) as well as in biocompatible cell medium (EMEM, Eagle's modified essential medium). The X-ray crystal structure of the first iodine-tagged and amino acid-functionalized NDI molecule, designed especially to facilitate the high resolution transmission electron microscopy (HR TEM) imaging whilst retaining its ability to self-assemble into a nanodimensional receptor in weakly polar solvents, is also described. A new hybrid material, NDI@SWNT, was prepared and characterized as dispersed in organic solvents and aqueous media and in the solid state by HR TEM, tapping mode atomic force microscopy (TM AFM), scanning electron microscopy (SEM), circular dichroism, Raman and fluorescence spectroscopies (steady-state single and two-photon techniques). We have been interested in the design and spectroscopic investigation of new nanomaterials with light emitting properties.[67] The NDI nanotubular receptor recently developed [55] should have the ability to bind via donor-acceptor interactions to carbon nanomaterials, in an analogous manner to that found in the exciting new hybrids containing perylenes in SWNTselectron acceptor composites for photovoltaic applications, reported by the groups of Hirsch [12][13][14] and Guldi.[14]We report our investigations at the formation of a new nanohybrid, denoted NDI@SWNT, in solution and on a preparative scale. We report here for the first time, the recognition and coating of the aromatic surface of ultra-purified SWNTs (provided by Thomas Swan Ltd, Elicarb SWNTs, and further steampuriffied to ensure they are free of catalytic impurities or carbonaceous materials from the nanotube synthesis, Supplementary Information) by a new iodine-and amino acid-derivatized NDI. Investigations into the properties of the new material synthesized (in bulk and in dispersions in CHCl 3 , EtOH, DMSO and serum free aqueous cell culture media such as EMEM) have been carried out by Raman, circular dichroism, FT IR, UV-vis-NIR and fluorescence spectroscopies and imaged at the nanoscale by HR TEM, SEM, EDS and TM AFM. The cellular translocation of the resulting NDI@SWNT complex was investigated by a combination of fluorescence microscopy techniques including fluorescence lifetime imaging and cytotoxicity assays (MTT) in cancerous and non-cancerous cell lines. Here we have used such techniques to probe the integrity of a new nanocomposite denoted NDI@SWNT in vitro. Such an approach could aid the future understanding of the mechanism of action of supramolecular materials at the cellular level and improve the synthetic design of nanohybrids for biomedical imaging and therapeutic applications. Results and Discussions Synthe...

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“…8 Several approaches have been taken to improve the stability of a CNT dispersion, for example sonication, 9 functionalization, [10][11][12] use of surfactants, 13-15 among many others. 16,17 The quality of these dispersions are usually quantified by techniques such as absorption, fluorescence and Raman spectroscopies, 18 as well as techniques like transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). 19,20 However, absorption spectroscopy in the ultraviolet-visible-near infrared (UV-Vis-NIR) range is described as the most accurate of these techniques.…”

Section: Introductionmentioning

confidence: 99%

The effect of different chemical treatments on the structure and stability of aqueous dispersion of iron- and iron oxide-filled multi-walled carbon nanotubes

Moraes¹,

Matos²,

Castro³

et al. 2011

J. Braz. Chem. Soc.

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O efeito de cinco diferentes tratamentos químicos (HNO 3 , H 2 SO 4 , H 2 O 2 , HNO 3 + H 2 SO 4 e HNO 3 + HCl) na homogeneidade, superfície, estrutura e dispersabilidade em água de nanotubos de carbono do tipo multi-paredes preenchidos com ferro ou óxido de ferro foi estudado através de difratometria de raios X (XRD), espectroscopias Raman, UV-Visível e fotoeletrônica de raios X (XPS), análise termogravimétrica (TG) e microscopia eletrônica de varredura (MEV). Os resultados indicaram que os tratamentos são efetivos na remoção de espécies carbonáceas diferentes de nanotubos, presentes na amostra. Com exceção do tratamento com H 2 O 2 , uma boa remoção das espécies contendo metal também foi observada. Além de aumentar a homogeneidade das amostras, os tratamentos também criam grupos carboxílicos e hidroxílicos superficiais, que afetam diretamente a dispersabilidade destas espécies em água. Dispersões estáveis de 2,24 × 10 -1 g L -1 de nanotubos em água foram obtidas após o tratamento com mistura de ácido sulfúrico e ácido nítrico.The effect of five different chemical treatments (HNO 3 , H 2 SO 4 , H 2 O 2 , HNO 3 + H 2 SO 4 and HNO 3 + HCl) on the homogeneity, surface chemistry, structure and dispersibility in water of ironand iron oxide-filled multi-walled carbon nanotube samples was evaluated by X-ray diffractometry (XRD), Raman, UV-Visible and X-ray photoelectron (XPS) spectroscopies, thermogravimetric analysis (TG) and scanning electron microscopy (SEM). The results indicate that the chemical treatments are generally effective in removing non-nanotube carbonaceous species present in the sample. With the exception of the H 2 O 2 treatment, the chemical treatments also offer good removal of free iron-species. Besides the increase in the sample homogeneity, the chemical treatments promoted an increase in the carboxyl and hydroxyl groups at the carbon nanotube surface, what directly affects the dispersibility of these carbon nanotubes in water. Dispersions of 2.24 × 10 -1 g L -1were obtained for the treated samples with a mixture of nitric and sulfuric acid. Keywords: carbon nanotubes, chemical treatment, CVD, nanostructures, nanomaterials IntroductionCarbon nanotubes (CNTs) have received much attention in the last years due to their extraordinary chemical and physical properties, arising from the combination of their typical morphology, structure and size.1 Many different processes have been described for the synthesis of CNTs. Among them, one of the most versatile is the catalytic chemical vapor deposition (CVD), which is based on the decomposition of a carbon source (usually a hydrocarbon) over metal nanocatalysts.2 Usually, the resulting samples are a mixture of CNTs and some impurities, such as other carbonaceous materials (graphite, amorphous carbon, fullerenes, carbon nano-structures, etc.) and the catalyst metal particles.3 These impurities are undesirable for a variety of applications, and different physical and/or chemical treatments are usually performed to remove them. 4 However, it should be noted th...

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Quantitative assessment of carbon nanotube dispersions by Raman spectroscopy

Cited by 63 publications

References 32 publications

Resistive–conductive transitions in the time-dependent piezoresponse of PVDF-MWCNT nanocomposites

Resistive–conductive transitions in the time-dependent piezoresponse of PVDF-MWCNT nanocomposites

Interactions Between Amino Acid‐Tagged Naphthalenediimide and Single Walled Carbon Nanotubes for the Design and Construction of New Bioimaging Probes

The effect of different chemical treatments on the structure and stability of aqueous dispersion of iron- and iron oxide-filled multi-walled carbon nanotubes

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