Carbon Nanotubes - Polymer Nanocomposites

Yellampalli, Siva

doi:10.5772/979

Cited by 47 publications

(9 citation statements)

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“…In accordance with this approach, the percolation chain is formed as a result of a random distribution of nanotubes over polymer matrix bulk. Therewith the position of the percolation threshold is roughly inversely proportional to the aspect ratio of nanotubes comprising the percolation chain [1][2][3]. Such a dependence is derived from the percolation theory, and the comparison of results of model calculations with the relevant experimental data usually results in a good coincidence for the percolation threshold values of such materials.…”

Section: Model Of Charge Transportmentioning

confidence: 92%

“…Nanocomposites on the basis of polymers doped with carbon nanotubes (CNT) present a typical example of such systems (see, for example Ref. [1][2][3][4] and the literature cited there). In such composites, at exceeding some critical value of CNT concentration, the percolation transition occurs which accompanies with the enhancement of the conductivity of the material by 10-12 orders of magnitude.…”

Section: Introductionmentioning

confidence: 99%

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Percolation Conduction of Carbon Nanocomposites

Бочаров

Елецкий

2020

IJMS

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Carbon nanocomposites present a new class of nanomaterials in which conducting carbon nanoparticles are a small additive to a non-conducting matrix. A typical example of such composites is a polymer matrix doped with carbon nanotubes (CNT). Due to a high aspect ratio of CNTs, inserting rather low quantity of nanotubes (on the level of 0.01%) results in the percolation transition, which causes the enhancement in the conductivity of the material by 10–12 orders of magnitude. Another type of nanocarbon composite is a film produced as a result of reduction of graphene oxide (GO). Such a film is consisted of GO fragments whose conductivity is determined by the degree of reduction. A distinctive peculiarity of both types of nanocomposites relates to the dependence of the conductivity of those materials on the applied voltage. Such a behavior is caused by a non-ideal contact between neighboring carbon nanoparticles incorporated into the composite. The resistance of such a contact depends sharply on the electrical field strength and therefore on the distance between neighboring nanoparticles. Experiments demonstrating non-linear, non-Ohmic behavior of both above-mentioned types of carbon nanocomposites are considered in the present article. There has been a model description presented of such a behavior based on the quasi-classical approach to the problem of electron tunneling through the barrier formed by the electric field. The calculation results correspond qualitatively to the available experimental data.

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Section: Model Of Charge Transportmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Percolation Conduction of Carbon Nanocomposites

Бочаров

Елецкий

2020

IJMS

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“…Covalent functionalization implies the formation of new chemical bonds, altering the original CNT structure. This reaction will change the carbon hybridization from sp 2 to sp 3 , causing the loss of the π-conjugation system of the graphene layer [42] responsible for most of the optical, electrical, and thermal properties of CNTs [43]. Despite this drawback, covalent functionalization presents many characteristics that make this approach highly attractive: it provides strong and very stable attachment of functional groups, entails higher selectivity, is more robust and better controlled than non-covalent functionalization, can be done in organic solvent or even without solvent, and offers a huge plethora of functional groups that can be used [44].…”

Section: Covalent Functionalizationmentioning

confidence: 99%

Carbon Nanotubes in Biomedicine

et al. 2020

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Nowadays, biomaterials have become a crucial element in numerous biomedical, preclinical, and clinical applications. The use of nanoparticles entails a great potential in these fields mainly because of the high ratio of surface atoms that modify the physicochemical properties and increases the chemical reactivity. Among them, carbon nanotubes (CNTs) have emerged as a powerful tool to improve biomedical approaches in the management of numerous diseases. CNTs have an excellent ability to penetrate cell membranes, and the sp 2 hybridization of all carbons enables their functionalization with almost every biomolecule or compound, allowing them to target cells and deliver drugs under the appropriate environmental stimuli. Besides, in the new promising field of artificial biomaterial generation, nanotubes are studied as the load in nanocomposite materials, improving their mechanical and electrical properties, or even for direct use as scaffolds in body tissue manufacturing. Nevertheless, despite their beneficial contributions, some major concerns need to be solved to boost the clinical development of CNTs, including poor solubility in water, low biodegradability and dispersivity, and toxicity problems associated with CNTs' interaction with biomolecules in tissues and organs, including the possible effects in the proteome and genome. This review performs a wide literature analysis to present the main and latest advances in the optimal design and characterization of carbon nanotubes with biomedical applications, and their capacities in different areas of preclinical research.

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“…The use of OAS to modify starch is a recognized chemical approach to introduce the biopolymer of starch such as tapioca starch into industrial applications. With respect to the rheological properties of OSA modified starches in aqueous medium, evidence have been provided to suggest that OSA side chains can aggregate into hydrophobic domains in water at even quite low concentrations [44,45].…”

Section: Introductionmentioning

confidence: 99%

“…The OSA-modified tapioca starch is amphiphilic in nature, which can potentially functionalize CNTs via non-covalent wrapping [45]. The physical adsorption of these copolymers onto CNTs surfaces increases the hydrophobic feature of the OSA, which may effectively prevent the aggregation of CNTs.…”

Section: Introductionmentioning

confidence: 99%

Surface Treatment of Carbon Nanotubes Using Modified Tapioca Starch for Improved Force Detection Consistency in Smart Cementitious Materials

Chia

Blazanin

Huang

et al. 2020

Sensors

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The remarkable mechanical properties and piezo-responses of carbon nanotubes (CNT) makes this group of nanomaterials an ideal candidate for use in smart cementitious materials to monitor forces and the corresponding structural health conditions of civil structures. However, the inconsistency in measurements is the major challenge of CNT-enabled smart cementitious materials to be widely applied for force detection. In this study, the modified tapioca starch co-polymer is introduced to surface treat the CNTs for a better dispersion of CNTs; thus, to reduce the inconsistency of force measurements of the CNTs modified smart cementitious materials. Cement mortar with bare (unmodified) CNTs (direct mixing method) and surfactant surface treated CNTs using sodium dodecyl benzenesulfonate (NaDDBS) were used as the control. The experimental results showed that when compared with samples made from bare CNTs, the samples made by modified tapioca starch co-polymer coated CNTs (CCNTs) showed higher dynamic load induced piezo-responses with significantly improved consistency and less hysteresis in the cementitious materials. When compared with the samples prepared with the surfactant method, the samples made by the developed CCNTs showed slightly increased force detection sensitivity with significantly improved consistency in piezo-response and only minor hysteresis, indicating enhanced dispersion effectiveness. The new CNT surface coating method can be scaled up easily to cater the potential industry needs for future wide application of smart cementitious materials.

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Carbon Nanotubes - Polymer Nanocomposites

Cited by 47 publications

References 0 publications

Percolation Conduction of Carbon Nanocomposites

Percolation Conduction of Carbon Nanocomposites

Carbon Nanotubes in Biomedicine

Surface Treatment of Carbon Nanotubes Using Modified Tapioca Starch for Improved Force Detection Consistency in Smart Cementitious Materials

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