Properties Carbon Nanotubes - Essay Example

The grapheme layer are rolled up into a cylinder to form carbon nanotubes (CNT). The formation of type SWNT or MWNT is decided by the shape and size of the particle and the surrounding environmental conditions. A buckyball is constituted of 60 carbon atoms arranged in 20 hexagons and 12 pentagons and look like “truncated icosahedron". The molecular scale-tubes (CNT) have remarkable properties. The different types of CNT have varied attributes in terms of electonic, thermal, and structural properties defined by its diameter, length, and chirality, or twist. The conducting or semiconducting properties of CNT are exhibited due to rolling direction of graphene layer which is quantified by ‘chiral vector’. The use of carbon in nanostructured forms of fullerenes (or buckyballs) and carbon nanotubes are important innovations in nanotechnology. These carbon structures have versatile applications in small scale and big scale processes from electronics to chemical industries. Bucky balls can play vital role in drug delivery system. Introduction Human mankind always is in the search of enhancing his standards of living based on scientific principles. Nanotechnology is one of the sophisticated techniques to achieve easy and comfortable future. Carbon is an inherent part of nature and approximately 20% of the human body is made up of carbon in the form of DNA, proteins, fats, and carbohydrates (The University of Wisconsin System, 2008). Carbon is capable of forming hardest and softest forms such as diamond and graphite which are found abundantly in nature. The use of carbon in nanostructured forms of fullerenes (or buckyballs) and carbon nanotubes (CNTs) are important innovations in nanotechnology due to their outstanding properties. These carbon structures have versatile applications in small scale and big scale processes from electronics to chemical industries. When a molecule is composed of only carbon atoms, it is called fullerene which may be shapes such as tube like (carbon nanotubes or buckytubes) or spherical (buckyballs). Carbon nanotubes Carbon nanotubes are large macromolecular forms of graphite invented by Sumio Iijima in 1991. Graphite sheets are carbon atoms bonded with each other by strong and weak interactions to give hexagonal appearance. These hexagonal sheets or grapheme layer are rolled up into a cylinder to form carbon nanotubes (CNT). CNT are classified into two types depending upon the number of sheets involved for forming a tube like structure: single walled nanotubes (SWNT), and multiwalled (MWNT). The formation of type SWNT or MWNT is decided by the shape and size of the particle and the surrounding environmental conditions (Makar & Beaudoin, 2003). CNT are synthesized by different methods on a large scale: arc discharge, laser ablation, high pressure carbon monoxide (HiPCO), and chemical vapor deposition (CVD) (Collins & Phaedon, 2000). Figure 1 shows a schematic of a single walled nanotubes produced by Prof. Charles M. Lieber Group (Nanotubes and Buckyballs, 2009, June 27). Despite of similar structures due to different orientation of along the axis of tube give rise to three types zigzag, armchair and chiral as shown in figure 2 (The University of Wisconsin System, 2008). The length of these carbon allotropes depends on growth conditions to obtain length-to-diameter ratio of up to 28,000,000:1 (Zheng, 2004). . Figure 1 a single walled nanotube (a) armchair, (b) zigzag, (c) chiral Figure 2 Bucky Balls Buckyball is a roundest and most symmetrical large molecule discovered by Richard Smalley, Robert Curl, and Harold Kroto in 1996. A buckyball is constituted of 60 carbon atoms arranged in 20 hexagons and 12 pentagons and look like “truncated icosahedron", as shown in figure 3 (The University of Wisconsin System, 2008). Buckminster Fuller created geodesic dome structures appearing like a large soccer ball and therefore also called as Buckminster fullerene (The University of Wisconsin System, 2008). Properties of nanotubes These molecular scale-tubes have remarkable properties. The different types of CNT have varied attributes in terms of electonic, thermal, and structural properties defined by its diameter, length, and chirality, or twist. The conducting or semiconducting properties of CNT are exhibited due to rolling direction of graphene layer which is quantified by ‘chiral vector’(Nanotubes and Buckyballs, 2009, June 27) and are governed by doping. Chirality decides the electronic behaviour eg. armchair being metallic are good conductors while other forms are semiconductors. The introduction of oxygen, change in size and mechanical deformation alters CNT conductivity. CNT are high quality and efficient field emitters when placed in electric field (Makar & Beaudoin, 2003). They display sturdiest properties which are proved by their moduli of elasticity that exceed 1 TPa. It has been reported that SWCNT have yield strength equivalent to 63 GPa and yield strains are on the order of 6% (Makar & Beaudoin, 2003). CNT are highly flexible which are capable of folding in circles, thin sheets and forming knots under different pressure and loadings (Makar & Beaudoin, 2003). CNT are highly efficient thermal conductors at room temperature which is proved from theory background and experimental results. Higher thermal conductivity is displayed along the length of the tube than width of the tube, delivering anisotropic heat conduction properties (Makar & Beaudoin, 2003). Buckyball is the one of the roundest and hardest molecules (two times harder than diamond), and therefore can be exploited in drug delivery systems. It is able to withstand high collision speed of a stainless steel plate at 15,000 mph without any deformation and bouncing (Nanotubes and Buckyballs, 2009, June 27). Present, planned and potential applications of carbon nanotubes and ‘bucky balls’ CNT are one of the vital molecular components of nanotechnology (Nanotubes and Buckyballs, 2009, June 27). AFM probe tips AFM probe tips can be made sharper with SWCNT rendering higher resolution image of a atom under investigation. Nanotube’s flexibility protects probe tip and ample surface from any damage and impact. Flat panel display screens The property of nanotubes to emit electrons in the electric field can be used to create an image on a phosphor screen. This feature can be used to modify the bulky electron guns of traditional TV sets by smaller CNT electron guns. 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Figure 1 shows a schematic of a single walled nanotubes produced by Prof. Charles M. Lieber Group (Nanotubes and Buckyballs, 2009, June 27). Despite of similar structures due to different orientation of along the axis of tube give rise to three types zigzag, armchair and chiral as shown in figure 2 (The University of Wisconsin System, 2008). The length of these carbon allotropes depends on growth conditions to obtain length-to-diameter ratio of up to 28,000,000:1 (Zheng, 2004). . Figure 1 a single walled nanotube (a) armchair, (b) zigzag, (c) chiral Figure 2 Bucky Balls Buckyball is a roundest and most symmetrical large molecule discovered by Richard Smalley, Robert Curl, and Harold Kroto in 1996.

A buckyball is constituted of 60 carbon atoms arranged in 20 hexagons and 12 pentagons and look like “truncated icosahedron", as shown in figure 3 (The University of Wisconsin System, 2008). Buckminster Fuller created geodesic dome structures appearing like a large soccer ball and therefore also called as Buckminster fullerene (The University of Wisconsin System, 2008). Properties of nanotubes These molecular scale-tubes have remarkable properties. The different types of CNT have varied attributes in terms of electonic, thermal, and structural properties defined by its diameter, length, and chirality, or twist.

The conducting or semiconducting properties of CNT are exhibited due to rolling direction of graphene layer which is quantified by ‘chiral vector’(Nanotubes and Buckyballs, 2009, June 27) and are governed by doping. Chirality decides the electronic behaviour eg. armchair being metallic are good conductors while other forms are semiconductors. The introduction of oxygen, change in size and mechanical deformation alters CNT conductivity. CNT are high quality and efficient field emitters when placed in electric field (Makar & Beaudoin, 2003).

They display sturdiest properties which are proved by their moduli of elasticity that exceed 1 TPa. It has been reported that SWCNT have yield strength equivalent to 63 GPa and yield strains are on the order of 6% (Makar & Beaudoin, 2003). CNT are highly flexible which are capable of folding in circles, thin sheets and forming knots under different pressure and loadings (Makar & Beaudoin, 2003). CNT are highly efficient thermal conductors at room temperature which is proved from theory background and experimental results.

Higher thermal conductivity is displayed along the length of the tube than width of the tube, delivering anisotropic heat conduction properties (Makar & Beaudoin, 2003). Buckyball is the one of the roundest and hardest molecules (two times harder than diamond), and therefore can be exploited in drug delivery systems. It is able to withstand high collision speed of a stainless steel plate at 15,000 mph without any deformation and bouncing (Nanotubes and Buckyballs, 2009, June 27). Present, planned and potential applications of carbon nanotubes and ‘bucky balls’ CNT are one of the vital molecular components of nanotechnology (Nanotubes and Buckyballs, 2009, June 27).

AFM probe tips AFM probe tips can be made sharper with SWCNT rendering higher resolution image of a atom under investigation. Nanotube’s flexibility protects probe tip and ample surface from any damage and impact. Flat panel display screens The property of nanotubes to emit electrons in the electric field can be used to create an image on a phosphor screen. This feature can be used to modify the bulky electron guns of traditional TV sets by smaller CNT electron guns. This could deliver cost and energy efficient ultra-flat (

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