Quantitative characterization of acidic groups on acid-treated multi-walled carbon nanotubes using 1-aminopyrene as a fluorescent probe

Nishikiori, Hiromasa; Tanigaki, Taku; Endo, Morinobu; Fujii, Tsuneo

doi:10.1016/j.carbon.2013.09.038

Cited by 12 publications

(11 citation statements)

References 41 publications

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“…Finally, the mean surface acidity of centrifuged cMWCNT suspensions was calculated using Equation 3 to be 19.09 ± 0.52 mmol/g. We know of only one other work to quantify the acidic surface groups of carbon material in centrifuged cCNT suspensions;[49] in brief, using fluorescence spectroscopy and 1-aminopyrene dye-treated samples, it was determined that MWCNTs oxidized for 24 h with nitric and sulfuric acids were 15 – 22% oxidized, which is in accordance with the 23% level of oxidation calculated for our centrifuged cMWCNT suspensions.…”

Section: Resultssupporting

confidence: 83%

“…[37–39] While the Boehm method has been applied to the analysis of oxidized carbon materials for over fifty years,[37–39,63–69] a standard protocol has rarely been followed for the analyses of cCNTs. [24,29,32,35,36,43,49,50,52,54,55,70–75] For example, there are different routines to determine endpoints, differences in base treatment times and agitation methods, differences in methods to address dissolved carbon dioxide, and differences in determining the mass of carbon material titrated. Herein, the first major parameter considered was the agitation method used to expose carbon materials to the chosen base – a process that can damage a carbon lattice and create new oxygen surface groups.…”

Section: Methodsmentioning

confidence: 99%

“…[37–39] Acidic groups on cCNT surfaces have been assessed qualitatively using thermogravimetric analysis (TGA),[40–43] semi-quantitatively using Fourier transform-infrared (FT-IR) spectroscopy,[24,44–46] and quantitatively using either fluorescence spectroscopy and dye-derivatized cCNTs,[47–49] x-ray photoelectron spectroscopy (XPS),[24,43–45,50,51] or acid-base titrimetry. [52–55] While these and other approaches have their advantages and limitations, a survey of the literature reveals that they have been used overwhelmingly to assess the surface acidity of un-centrifuged cCNT suspensions, and rarely to assess the surface acidity of cCNT suspensions purified by centrifugation.…”

Section: Introductionmentioning

confidence: 99%

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Enriched surface acidity for surfactant-free suspensions of carboxylated carbon nanotubes purified by centrifugation

Braun

Draper

Pantano

2016

Analytical Chemistry Research

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It is well known that surfactant-suspended carbon nanotube (CNT) samples can be purified by centrifugation to decrease agglomerates and increase individually-dispersed CNTs. However, centrifugation is not always part of protocols to prepare CNT samples used in biomedical applications. Herein, using carboxylated multi-walled CNTs (cMWCNTs) suspended in water without a surfactant, we developed a Boehm titrimetric method for the analysis of centrifuged cMWCNT suspensions and used it to show that the surface acidity of oxidized carbon materials in aqueous cMWCNT suspensions was enriched by ~40% by a single low-speed centrifugation step. This significant difference in surface acidity between un-centrifuged and centrifuged cMWCNT suspensions has not been previously appreciated and is important because the degree of surface acidity is known to affect the interactions of cMWCNTs with biological systems.

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Section: Resultssupporting

confidence: 83%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enriched surface acidity for surfactant-free suspensions of carboxylated carbon nanotubes purified by centrifugation

Braun

Draper

Pantano

2016

Analytical Chemistry Research

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“…Zhou et al reported [9] nanodefects produced by a sulfonitric mixture at 373 K, as revealed by TEM observations, Raman spectroscopy and FTIR measurements. Nishikori et al [13] performed oxidation studies using an acidic mixture and employed XPS and the UV-vis absorption method using 1-aminopyrene as a fluorescent probe.…”

Section: Introductionmentioning

confidence: 99%

Surface modification of multiwall carbon nanotubes by sulfonitric treatment

Gómez

Rendtorff

Aglietti

et al. 2016

Applied Surface Science

100

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Carbon nanotubes are widely used for electronic, mechanical, and optical devices due to their unique structural and quantum characteristics. The species generated by oxidation on the surface of these materials permit binding new reaction chains, which improves the dispersibility, processing and compatibility with other materials. Even though different acid treatments and applications of these CNT have been reported, relatively few research studies have focused on the relationship between the acid treatment and the formation of nanodefects, specific oxidized species or CNT surface defects. In this work, multiwall carbon nanotube (MWCNT) oxidation at 90 • C was characterized in order to determine the acid treatment effect on the surface. It was found that oxidized species are already present in MWCNT without an acid treatment, but there are not enough to cause water-based dispersion. The species were identified and quantified by infrared spectroscopy and X-ray photoelectron spectroscopy. Also, transmission electron microscopy observations showed not only modifications of the oxidized species, but also morphological damage on the surfaces of MWCNT after being subjected to the acid treatment. This effect was also confirmed by Raman spectroscopy. The acid treatment generates higher oxidized species, decreasing the zeta potential in the whole pH range.

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“…La Figura 6.6 muestra los difractogramas obtenidos. El pico de difracción a 26° (2θ) se refiere al plano (002) de la estructura hexagonal del grafito (Lu et al, 2008;Nishikiori et al, 2014;Rosca et al, 2005). Se observa que para las muestras T90, T110 y T130 este pico se aparta levemente hacia ángulos más bajos, indicando que la distancia entre las capas del grafito (capas del nanotubo) d002 se expande (de 3,42 a 3,45 Å) debido a la intercalación de iones sulfato y nitrato entre los cilindros coaxiales de grafeno que forman la estructura de los NTC (Li et al, 2016).…”

Section: Difracción De Rayos X (Drx)unclassified

Materiales nanoestructurados de zirconia: Materiales densos y compositos con nanotubos de carbono (NTC)

Gómez¹

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El óxido de zirconio o zirconia (ZrO2) es un material que, por su versatilidad, abarca un amplio campo de aplicación, desde los cerámicos estructurales como los refractarios; a los biomateriales y las celdas de combustibles como materiales funcionales. La versatilidad de la zirconia se debe a que presenta diferentes estructuras cristalinas y cada una de ellas tiene propiedades propias que se diferencian de las demás. Al dopar la zirconia con 8 mol% de ytria, esta desarrolla una estructura cúbica a temperatura ambiente en la que se promueve una mejora en la conductividad iónica, sin embargo, las propiedades mecánicas de este material presentan ciertas desventajas frente a materiales de zirconia tetragonal (3YZ), y en especial, este material exhibe una tenacidad a la fractura mucho menor además de un importante crecimiento de grano. En los últimos años, ha habido un gran interés en el desarrollo de materiales cerámicos que contengan nanotubos de carbono con el fin de generar una mayor resistencia y tenacidad a la fractura (KIc) para aplicaciones estructurales. Los nanotubos de carbono (NTC) tienen alta superficie específica y presentan excelentes propiedades mecánicas y de conductividad. Debido a estas propiedades es que se ha intentado producir materiales cerámicos en los que los NTC actúen como refuerzo dentro de la matriz cerámica. No obstante la incorporación de estas fibras al material cerámico para producir alguna mejora requiere una fuerte unión entre las partículas de la matriz y los NTC. La heterocoagulación electrostática se postula como un método efectivo para producir una buena dispersión de los NTC en la matriz cerámica y además, mediante este método se producen una fuerte interacción entre los NTC y la matriz cerámica, aportando al anclaje de los tubos en la matriz y por lo tanto, potenciando el refuerzo del composito. El objetivo de esta tesis es aportar conocimiento acerca del efecto que tiene la adición de una pequeña cantidad de nanotubos de carbono (1% p/p) en una matriz de zirconia cúbica, analizando diversas propiedades de los materiales compuestos y comparándolos con el material formado solamente por zirconia. En una primera etapa se realizará la caracterización de las materias primas: zirconia y nanotubos de carbono (Capítulo 4). Luego, se estudiarán las propiedades texturales y mecánicas de los materiales sinterizados en forma convencional de zirconia monoclínica (m-ZrO2) y dopada con 3 y 8 mol% de Y2O3, 3YZ y 8YZ, respectivamente; y en particular, se caracterizarán materiales de 8YZ sinterizados por dos vías alternativas: sinterización en dos pasos y spark plasma sintering (SPS) (Capítulo 5). En una segunda etapa, se abordará la funcionalización de los NTC mediante un tratamiento ácido a diferentes temperaturas (Capítulo 6). En la etapa final de esta tesis se estudiarán los materiales conformados por 8YZ y 1% p/p de NTC, procesados mediante heterocoagulación electrostática (Capítulo 7). Se profundizará el estudio sobre el efecto que tiene la introducción de NTC en la dureza Vickers (Hv) y tenacidad a la fractura (KIc) medidas por el método de indentación, la dureza y el módulo de elasticidad obtenidas por microindentación, y la resistencia a la flexión del composito 8YZ-NTC, en conjunto con un análisis de la resistencia al desgaste que presentan estos compositos.

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Quantitative characterization of acidic groups on acid-treated multi-walled carbon nanotubes using 1-aminopyrene as a fluorescent probe

Abstract: Acidic functional groups produced on the surface of acid-treated multi-walled carbon nanotubes

Cited by 12 publications

References 41 publications

Enriched surface acidity for surfactant-free suspensions of carboxylated carbon nanotubes purified by centrifugation

Enriched surface acidity for surfactant-free suspensions of carboxylated carbon nanotubes purified by centrifugation

Surface modification of multiwall carbon nanotubes by sulfonitric treatment

Materiales nanoestructurados de zirconia: Materiales densos y compositos con nanotubos de carbono (NTC)

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