Carboxylated Carbon Nanotubes under External Electrical Field: An Ab Initio Investigation

Silva, Leandro B. da; Fagan, Solange B.; Mota, Ronaldo

doi:10.1021/jp810878y

Cited by 13 publications

(13 citation statements)

References 35 publications

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“…). The following is found:

p = α E + β,

where p is the module of the electric dipole moments, E is the applied electric field, α represents the electric susceptibility , and β the electric dipole moment in the absence of an electric field. For pristine and functionalized CCN with carboxyl, amine, amide, or hydroxyl groups Eq.…”

Section: Resultsmentioning

confidence: 99%

“…The chemical functionalization of nanotubes can also facilitate their interactions with other chemical groups . Nevertheless, studies have reported that there are other ways to change electronically the nanotubes properties . One of them, studied here, is the application of electric fields that can polarize the system, resulting in an induced dipolar momentum of the tube in the incident field direction .…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, studies have reported that there are other ways to change electronically the nanotubes properties . One of them, studied here, is the application of electric fields that can polarize the system, resulting in an induced dipolar momentum of the tube in the incident field direction . The polarized nanotube, which previously presented a nonpolar character, may then present an increase of the physical interaction or bind chemically itself to a polar molecule, such as water, for example .…”

Section: Introductionmentioning

confidence: 99%

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Pristine and functionalized capped carbon nanotubes under electric fields

Menezes

Mota

Zanella

et al. 2013

Physica Status Solidi (b)

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, Phone: þ55 (55) 3220 1234, Fax: þ55 (55) 3222 6484The structural and electronic properties of end-capped carbon nanotubes (CCN) functionalized by carboxyl, amine, amide, and hydroxyl chemical groups under the action of electric fields are investigated through first-principles simulations based on density functional theory. Changes in the original properties of the functionalized capped nanotubes are observed due to the application of external electrical fields and the responses for different intensities are shown to be nonlinear. It is demonstrated that there are optimum values for the electric field to obtain the most stable binding energies for the studied systems. In all cases, the energy levels are rearranged to stabilize the systems and electric dipole moments are induced toward the incident electric field. It is also shown that these electric dipole moments generate polarized nanotubes and the previously weak physical interactions between molecules with the tube surface would become stronger and, by binding chemically, allow the manipulation of the intrinsic properties of the nanotubes.The structural and electronic properties of end-CCN pristine and functionalized by carboxyl, amine, amide, and hydroxyl chemical groups under the action of electric fields are investigated through first-principles simulations based on the density functional theory.

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“…). The following is found:

p = α E + β,

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Pristine and functionalized capped carbon nanotubes under electric fields

Menezes

Mota

Zanella

et al. 2013

Physica Status Solidi (b)

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“…While many density functional theory (DFT) calculations have been conducted on covalently functionalized CNTs in order to determine the influence of grafted organic groups on the electronic structure of CNTs, [46][47][48][49] to the best of our knowledge no mechanistic studies of the formation of these functional groups on CNT surface have been undertaken. Such multistep mechanistic studies are usually limited to the preliminary interaction between CNTs surfaces and atomic oxygen [50][51][52] or NO 2 + ions.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Studies on the Carbon‐Nanotube Surface Oxidation by Nitric Acid: Interplay between Functionalization and Vacancy Enlargement

Gerber

Oubenali

Bacsa

et al. 2011

Chemistry A European J

102

105

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The nitric acid oxidation of multiwalled carbon nanotubes leading to surface carboxylic groups has been investigated both experimentally and theoretically. The experimental results show that such a reaction involves the initial rapid formation of carbonyl groups, which are then transformed into phenol or carboxylic groups. At room temperature, this reaction takes place on the most reactive carbon atoms. At higher temperatures a different mechanism would operate, as evidenced by the difference in activation energies. Experimental data can be partially related to first-principles calculations, showing a multistep functionalization mechanism. The theoretical aspects of the present article have led us to propose the most efficient pathway leading to carboxylic acid functional groups on the surface. Starting from mono-vacancies, it ends up with the synergistic formation of dangling -COOH groups and the enlargement of the vacancies.

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“…[30][31][32][33] Ab initio calculations indicate that the longitudinal polarizability is roughly proportional to its length and that the presence of functional groups on CNTs does not alter the polarization characteristics significantly. 34 Due to the myriad applications of aligned CNT deposits on substrates, the process of alignment of CNTs in presence of applied electric field has recently generated great interest in the scientific community. Overall, under an applied electric field, charged CNTs experience two types of motion: electrophoretic rotation followed by electrophoretic migration leading to deposition.…”

Section: Introductionmentioning

confidence: 99%

Predictive model for alignment and deposition of functionalized nanotubes using applied electric field

Mostafa

Banerjee

2014

Journal of Applied Physics

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Effective hybrid graphene/carbon nanotubes field emitters by electrophoretic depositionMyriad applications, including sensors and supercapacitors, employ substrates decorated with patterned carbon nanotubes (CNTs) in order to leverage the significant anisotropy in their properties. In the present study, a unique continuum mechanics based model was developed to predict the alignment and migration timescales of CNTs for realistic lab-scale electrophoretic deposition (EPD), which is a popular technique to create aligned deposits of pristine and functionalized CNTs without embedded catalysts. This model was initially validated based on results from molecular dynamics simulations to check for mutual consistency. EPD is a complex process that involves electrophoretic alignment and migration of CNTs towards the substrate, displacement of solvent molecules from the surface of substrate by overcoming an energy barrier, followed by deposition. We simulated ACOOH functionalized CNTs of varying length under a range of applied electric fields (1 V/nm to 5 V/nm) to understand the mechanics of electrophoretic alignment and deposition. The dynamics of alignment and deposition were related to the molecular interactions between the various constituents by calculating friction parameters. The results from the parametric study, which is limited to length scales accessible to molecular dynamics simulations, was scaled up to CNTs of micrometer-scale length by comparing the results with solutions to the continuum scale model. The results indicate that the timescale for rotational alignment of realistic CNTs is of the order of seconds and several orders of magnitudes faster compared to the timescale for migration, which is of the order of thousands of seconds for a channel of diameter of 100 lm. V C 2014 AIP Publishing LLC. [http://dx.

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Carboxylated Carbon Nanotubes under External Electrical Field: An Ab Initio Investigation

Cited by 13 publications

References 35 publications

Pristine and functionalized capped carbon nanotubes under electric fields

Pristine and functionalized capped carbon nanotubes under electric fields

Theoretical and Experimental Studies on the Carbon‐Nanotube Surface Oxidation by Nitric Acid: Interplay between Functionalization and Vacancy Enlargement

Predictive model for alignment and deposition of functionalized nanotubes using applied electric field

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