Carbon Nanotubes and its Applications in Diverse Areas of Science and Engineering: A Critical Overview

Author(s):  
Sukanchan Palit
Author(s):  
Rafael Vargas-Bernal

There is enormous interest in carbon nanomaterials, due to their exceptional physical properties, from the perspective of science and engineering of materials applied to the electronics industry. Until now, significant progress has been made towards understanding the mechanisms of electrical conductivity of carbon nanotubes and graphene. However, scientists around the world even today continue studying these mechanisms, for exploiting them fully in different electronic applications with a high technological impact. This article discusses the mechanisms of electrical conductivity of both nanomaterials, analyzes the present implications, and projects its importance for future generations of electronic devices. In particular, it is important to note that different mechanisms may be identified when these nanomaterials are used individually, when they are incorporated as fillers in composite materials or hybrid materials, or even when they are doped or functionalized. Finally, other electrical variables with important role in electrical conductivity of these materials are also explored.


Author(s):  
Rafael Vargas-Bernal

There is enormous interest in carbon nanomaterials due to their exceptional physical properties, from the perspective of science and engineering of materials applied to the electronics industry. Significant progress has been made towards understanding the mechanisms of electrical conductivity of carbon nanotubes and graphene. However, scientists around the world continue studying these mechanisms to exploit them fully in different electronic applications with a high technological impact. This chapter discusses the mechanisms of electrical conductivity of both nanomaterials, analyzes the present implications, and projects its importance for future generations of electronic devices. In particular, it is important to note that different mechanisms may be identified when these nanomaterials are used individually, when they are incorporated as fillers in composite materials or hybrid materials, or even when they are doped or functionalized. Finally, other electrical variables with important role in electrical conductivity of these materials are also explored.


2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Jorge Fernandes de Morais ◽  
Assed Naked Haddad ◽  
Laia Haurie

Nanotechnology has brought significant innovations in science and engineering. Carbon nanotube has been considered a new and outstanding material in nanoscience field with great potential application in the construction industry. The main objective of this study is to analyze the behavior of cementitious materials produced with the insertion of carbon nanotubes of multiple walls in different concentrations and compare their physic-mechanical properties with plain mortar. This research covers the examination of nanoscale cement products and the use of carbon nanotubes to increase the strength and durability of cementitious composites. Three different ratios of carbon nanotubes have been searched: 0.20, 0.40, and 0.60%. To evaluate the mechanical properties of the samples, destructive and nondestructive tests were carried out to obtain compressive strength, tensile strength by diametrical compression, and dynamic modulus of elasticity as well as to determine their deformation properties. Methods of instrumentation such as scanning electron microscopy and porosity were also used in the analysis of microstructure of the materials. The study presents graphs, tables, and figures describing the behavior of CNT added to mortars samples, allowing a better understanding of the use of this new material in the construction industry.


Author(s):  
Jun Jiao

HREM studies of the carbonaceous material deposited on the cathode of a Huffman-Krätschmer arc reactor have shown a rich variety of multiple-walled nano-clusters of different shapes and forms. The preparation of the samples, as well as the variety of cluster shapes, including triangular, rhombohedral and pentagonal projections, are described elsewhere.The close registry imposed on the nanotubes, focuses attention on the cluster growth mechanism. The strict parallelism in the graphitic separation of the tube walls is maintained through changes of form and size, often leading to 180° turns, and accommodating neighboring clusters and defects. Iijima et. al. have proposed a growth scheme in terms of pentagonal and heptagonal defects and their combinations in a hexagonal graphitic matrix, the first bending the surface inward, and the second outward. We report here HREM observations that support Iijima’s suggestions, and add some new features that refine the interpretation of the growth mechanism. The structural elements of our observations are briefly summarized in the following four micrographs, taken in a Hitachi H-8100 TEM operating at an accelerating voltage of 200 kV and with a point-to-point resolution of 0.20 nm.


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