Carbon Nanotubes PDF

Carbon Nanotubes CONTENTS - What are carbon nanotubes? - Classification of carbon nanotubes Single-Walled Carbon Nanotubes (SWCTN) Multi-Walled Carbon Nanotubes (MWCTN) - Properties of Carbon Nanotubes Electronic Mechanical Thermal - Methods of Synthesi...

Carbon Nanotubes CONTENTS - What are carbon nanotubes? - Classification of carbon nanotubes Single-Walled Carbon Nanotubes (SWCTN) Multi-Walled Carbon Nanotubes (MWCTN) - Properties of Carbon Nanotubes Electronic Mechanical Thermal - Methods of Synthesis of Carbon Nanotubes - Application of Carbon Nanotubes  What are carbon nanotubes? Allotropes Carbon nanotubes (CNT's) are allotropes carbon, like diamond, graphite and fullerenes. Diamond Graphite The term allotrope refers to one or Hybridization: sp3 Hybridization: sp2 more forms of a In which four In which each atom is connected bonds are directed evenly to three carbons (120°) in the chemical element towards the plane, and a weak bond is present in that occur in the corners of a the axis. regular same physical tetrahedron. state. Fullerenes Graphene Carbon Nanotubes Hybridization: sp2 Hybridization: sp2 Hybridization: sp2 Graphene is a 2D structure of carbon CNTs are tubular in shape, made of atoms with graphite. hexagonal Outer diameter from about 3 nm to crystalline 30 nm. structure There are CNT´s of Single-Walled, Double-Walled and Multi-Walled N. Saifuddin et al. Carbon Nanotubes: A Review on Structure and Their Interaction with Proteins. DOI: https://doi.org/10.1155/2013/676815 Velram BalajiMohan et al. Graphene-based materials and their composites: A review on production, applications and product limitations. DOI:  Classification of carbon nanotubes Classification of CNT On the basis of Sheet On the basis of Armchair Zig-Zag Chiral Tubes SWNT DWNT MWNT Ekta Singh et al. Carbon Nanotube: A Review on Introduction, Fabrication Techniques and Optical Applications. DOI: 10.12691/nnr-4-4-1 Once they discovered nanotubes, researchers set about trying to figure out ways to produce lots of them. There are three methods that various companies have developed to produce carbon nanotubes in bulk quantities and at a lower cost: The first method is called high-pressure carbon monoxide deposition, or HIPCO. This method involves a heated chamber through which carbon monoxide gas and small clusters of iron atoms flow. When carbon monoxide molecules land on the iron clusters, the iron acts as a catalyst and helps a carbon monoxide molecule break up into a carbon atom and an oxygen atom. The carbon atom bonds with other carbon atoms to start the nanotube lattice; the oxygen atom joins with another carbon monoxide molecule to form carbon dioxide gas, which then floats off into the air. The second method is called chemical-vapor deposition, or CVD. In this method, a hydrocarbon-say, methane gas (one carbon atom and four hydrogen atoms)- flows into a heated chamber containing a substrate coated with a catalyst, such as iron particles. The temperature in the chamber is high enough to break the bonds between the carbon atoms and the hydrogen atoms in the methane molecules-resulting in carbon atoms with no hydrogen atoms attached. Those carbon atoms attach to the A brand-new method uses a plasma process to produce nanotubes. Methane gas, used as the source of carbon, is passed through a plasma torch. Nobody's revealed the details of this process yet, such as what, if any, catalyst is used. One of the initial claims is that this process is 25 times more efficient at producing nanotubes than the other two methods.  Classification of carbon nanotubes CNTs are cylindrical graphene sheets of sp2-bonded carbon atoms. In CNTs the graphene sheet is rolled upon itself to form different allotropes of carbon, including graphite, fullerenes and CNTs. Single-walled CNTs Double-walled CNTs Multi-walled CNTs Carbon nanotubes are classified in the following three types based on the number of tubes present in the CNTs. These nanotubes are made of These nanotubes are MWNTs consist of multiple a single graphene sheet made of two layers of graphene rolled rolled upon itself with a concentric carbon upon itself with diameters diameter of 1–2 nm. The nano-tubes in which the ranging from 2 to 50 nm length can vary depending on outer tube encloses the depending on the number of the preparation methods. inner tube. graphene tubes. These tubes have an approximate inter-layer distance of 0.34 nm. N. Saifuddin et al. Carbon Nanotubes: A Review on Structure and Their Interaction with Proteins. DOI: https://doi.org/10.1155/2013/676815 Khalid Saeed Ibrahim. Carbon nanotubes–properties and applications: a review. DOI: http://dx.doi.org/DOI:10.5714/CL.2013.14.3.131  Classification of carbon nanotubes: Single Walled There are three types of CNTs based on chirality armchair carbon nanotubes, zigzag carbon nanotubes, and chiral carbon nanotubes. The difference in these types of carbon nanotubes are created depending on how the graphite is “rolled up” during its creation process. The choice of rolling axis relative to the hexagonal network of the graphene sheet and the radius of the closing cylinder allows for different types of SWCNTs. Chirality of a SWNT is obtained from its chiral vector C,defined by a pair of integers (n, m) obtained from the arrangement of the graphite hexagons with respect to the SWNT axis. The armchair The zigzag configuration with conformation is chiral vectors (n, n) characterized by is characterized by vectors (n,0) and the perpendicular has a V-shape shape of the chair perpendicular to the to the tube axis. tube axis. The chirality of SWNTs determines their All other vector compositions are conductivity, allowing for their potential described as chiral or helical. development into a wide variety of SWNT- based electronic switching devices. N. Saifuddin et al. Carbon Nanotubes: A Review on Structure and Their Interaction with Proteins. DOI: https://doi.org/10.1155/2013/676815 Ekta Singh et al. Carbon Nanotube: A Review on Introduction, Fabrication Techniques and Optical Applications. DOI: 10.12691/nnr-4-4-1  Classification of carbon nanotubes: Multi Walled Multiwalled carbon nanotubes can be formed in two structural models: Russian Doll model and Parchment Model. Russian Doll Parchment Model When a carbon nanotube contains another On another hand, when a single graphene sheet is nano-tube inside it and the outer nanotube has a wrapped around itself manifold times, the same as greater diameter than thinner nanotube, it is a rolled-up scroll of paper, it is called the Parchment called the RussianDoll model. Model. N. Saifuddin et al. Carbon Nanotubes: A Review on Structure and Their Interaction with Proteins. DOI: https://doi.org/10.1155/2013/676815 Khalid Saeed Ibrahim. Carbon nanotubes–properties and applications: a review. DOI: http://dx.doi.org/DOI:10.5714/CL.2013.14.3.131  General comparison between SWNT and MWNT SWNT MWNT Single layer of graphene Multiple layers of graphene Catalyst is required for synthesis Can be produced without catalyst Bulk synthesis is difficult as it requires Bulk synthesis is easy proper control over growthand atmospheric condition Purity is poor Purity is high A chance of defect is more during A chance of defect is less but once functionalization occurred it is difficult to improve Less accumulation in the body More accumulation in the body Separated from Characterization and evaluation is easy It has very complex structure each other by approximately 0.34 It can be easily twisted and is more It cannot be easily twisted nm as a result of pliable van der Waals Easy characterization and evaluation Difficult characterization and evaluation forces between adjacent layers. Ali Eatemadi et al. Carbon nanotubes: properties, synthesis, purification, and medical applications. https://doi.org/10.1186/1556-276X-9-393 Deepak G Panpatte et al. Nanotechnology for Agriculture. DOI: 10.1007/978-981-32-9370-0_8  Carbon nanotubes: properties It is well known that CNTs are intrinsically composed of pure carbon atoms that arrange and interact with each other by the strong sp2 carbon-carbon chemical bonds and form the unique geometric structure of a carbon network; this gives CNTs fascinating and attractive properties, such as electronic, mechanical, and thermal properties. These properties are not only strongly dependent on the structure of nanotubes but also are all interrelated and influenced. Typically, the strong chemical bonding in the carbon network endows CNTs with strong Theoretically, SWCNTs mechanical modulus, high may really have tensile thermal transport, as well as strength hundreds of remarkable electrical times stronger than properties. steel. H.Qiu et al. Chapter 2 - Structure and Properties of Carbon Nanotubes. DOI: https://doi.org/10.1016/B978-0-323-41481-4.00002-2  Carbon nanotubes: Electronic properties The nanometer dimensions and the highly symmetric structure of CNTs, as well as the unique electronic structure of a 2D graphene sheet, are listed as the main reasons for the extraordinary electronic properties of 1D CNT structures. The theory has demonstrated that the electronic properties of Single-walled CNTs SWCNTs depend sensitively on the diameter and helicity of the tubes, in other words, on the indices (n, m). An SWCNT can geometrically be viewed as a graphene sheet Metallic Both Semiconducting rolled up to form a hollow cylinder; thus, the physics behind the electronic properties of CNTs can be traced back to the electronic structure of graphene. Roghayeh Ghasempour et al. CNT Basics and Characteristics. DOI: http://dx.doi.org/10.1016/B978-0-323-48221-9.00001-7 Ting Lei et al. Separation of Semiconducting Carbon Nanotubes for Flexible and Stretchable Electronics Using Polymer Removable Method. DOI:  Carbon nanotubes: Electronic properties Single-walled CNTs The theory has demonstrated that the electronic properties of SWCNTs depend sensitively on the diameter and helicity of the tubes, in other words, on the indices (n, m). Metallic Both Semiconducting Chirality map of SWNTs. The metallicity is governed by their chirality. If |n−m| is a multiple of 3, the nanotubes are metallic (blue). All the reminders are semiconducting (yellow). Roghayeh Ghasempour et al. CNT Basics and Characteristics. DOI: http://dx.doi.org/10.1016/B978-0-323-48221-9.00001-7 Ting Lei et al. Separation of Semiconducting Carbon Nanotubes for Flexible and Stretchable Electronics Using Polymer Removable Method. DOI:  Carbon nanotubes: Mechanical Properties The mechanical properties of CNTs are a direct consequence of the nature of the chemical bonds between the carbon atoms and of the particular geometrical arrangement of such bonds in CNTs. Since σ bonding is probably Young’s modulus and the elastic response to deformation are two the strongest chemical bond important parameters that characterize the mechanical properties of known in nature, CNTs, CNTs. structured with all σ bonding, are expected to possess exceptional mechanical With Single-walled CNTs properties. Researchers have also demonstrated that expected to have Diameters between Young’s modulus is 1 and 2 nm independent of tube 1 TPa chirality but dependent on tube diameter. Multi-walled CNTs expected to have 1.1 – 1.3 TPa Roghayeh Ghasempour et al. CNT Basics and Characteristics. DOI: http://dx.doi.org/10.1016/B978-0-323-48221-9.00001-7  Carbon nanotubes: Mechanical Properties The extraordinary elastic response of a CNT to deformation has also attracted special attention. Atomic Force Microscopy (AFM) measurements have revealed that CNTs can be bent to form sharp U-tubes and loops with small curvatures, testifying to their flexibility, toughness, and capacity for reversible deformations. Although most hard materials fail with a strain of 1% or less owing to propagation of dislocations and defects, CNTs can sustain up to 15% tensile strain before fracture. Thus, assuming 1 TPa for Young’s modulus of an SWCNT, its tensile strength can be as high as 150 GPa, which is an order of magnitude higher than any other material. Roghayeh Ghasempour et al. CNT Basics and Characteristics. DOI: http://dx.doi.org/10.1016/B978-0-323-48221-9.00001-7 Young's modulus(E) evaluates the elasticity of a material, which is the relation between the deformation of a material and the power needed to deform it. Young's modulus (E) is defined as the ratio of the stress applied to the material along the longitudinal axis of the specimen tested and the deformation or strain, measured on that same axis. Young's Modulus is also known as tensile modulus, elastic modulus or modulus of elasticity. Tensile strength is the value of the maximum stress that a material can handle. This is the limit between plasticity zone and rupture zone. Tensile strength is an ability of plastic material to withstand maximum amount of tensile stress while being pulled or stretched without failure. It is the point when a material goes from elastic to plastic deformation. Elastic deformation - When the stress is removed, the material returns to the dimension it had before the load was applied. Valid for small strains (except the case of rubbers). Deformation is reversible, non-permanent Plastic deformation - When the stress is removed, the material does not return to its previous dimension but there is a permanent, irreversible deformation.  Carbon nanotubes: Mechanical Properties Mechanical Properties of Carbon Nanotubes Compared With Some Engineering Materials Materials Young’s Modulus Tensile Strength Density (GPa) (GPa) (g/cm3) MWCNT 1200 ~150 2.6 SWCNT 1054 ~150 1.3 Graphite (in- 350 2.5 2.6 plain) Steel 208 0.4 7.8 Wood 16 0.08 0.6 Roghayeh Ghasempour et al. CNT Basics and Characteristics. DOI: http://dx.doi.org/10.1016/B978-0-323-48221-9.00001-7  Carbon nanotubes: Thermal Properties The CNTs show a broad range of thermal properties stemming from their relation to the corresponding 2d graphene sheet and from their unique structure and nanometer dimensions. Depending on their structure and order (individual, films, bundled, buckypapers, etc.), carbon nanotubes (CNTs) demonstrate different values of thermal conductivity, from the level of thermal insulation with the thermal conductivity of 0.1 W/mK to such high values as 6600 W/mK. Diamond, which has the thermal conductivity in the range K = 1000–2200W/mK. Bogumiła Kumanek et al. Thermal conductivity of carbon nanotube networks: a review. DOI: https://doi.org/10.1007/s10853-019-03368-0 Alexander A. Balandin. Superior Thermal Conductivity of Single-Layer Graphene. UC Riverside DOI: https://doi.org/10.1021/nl0731872  Synthesis of carbon nanotubes There are three methods commonly used to synthesize CNTs: (1) the chemical vapor deposition (CVD) technique, (2) the laser-ablation technique, and (3) the carbon arc-discharge technique. The basic elements for the formation of nanotubes are: advantages source of carbon SWNTC production cost disadvantages MWNTC purity of CNTs catalyst Methods sufficient energy The common feature of these methods is CNTs with requested properties addition of energy to a carbon source to produce fragments (groups or single C atoms) that can recombine to generate CNT. The energy source may be electricity from an arc discharge, heat from a furnace (∼900 °C) for CVD, or the high- intensity light from a laser(laser ablation). Ali Eatemadi et al. Carbon nanotubes: properties, synthesis, purification, and medical applications. DOI: https://doi.org/10.1186/1556-276X-9-393 N.Saifuddin et al. Carbon Nanotubes: A Review on Structure and Their Interaction with Proteins. DOI: http://dx.doi.org/10.1155/2013/676815  Synthesis of carbon nanotubes One of standard methods for the production of carbon nano-tubes is chemical vapor deposition or CVD. There are many different types of CVD such as: Catalytic chemical vapor deposition (CCVD) Thermal or plasma-enhanced (PE) Oxygen assisted CVD Water-assisted CVD Microwave plasma (MPECVD) Radio frequency CVD (RF-CVD) Hot filament (HFCVD) But catalytic chemical vapor deposition (CCVD) is currently the standard technique for the synthesis of carbon nanotubes. Ali Eatemadi et al. Carbon nanotubes: properties, synthesis, purification, and medical applications. DOI: https://doi.org/10.1186/1556-276X-9-393 Jan Prasek et al. Methods for carbon nanotubes synthesis—review. DOI: : https://doi.org/10.1039/c1jm12254a  Synthesis of carbon nanotubes: Growth mechanism One of the mechanisms consists out of three steps. The first a precursor to the formation of nanotubes and fullerenes, C2, is formed on the surface of the metal 1 catalyst particle. From this metastable carbide particle, a rodlike carbon is formed rapidly. Secondly, there is a slow graphitization of its wall. This mechanism is based on in-situ TEM observations. The exact atmospheric conditions depend 2 on the technique used, later on, these will be explained for each technique as they are specific for a technique. Ali Eatemadi et al. Carbon nanotubes: properties, synthesis, purification, and medical applications. DOI: https://doi.org/10.1186/1556-276X-9-393 Jan Prasek et al. Methods for carbon nanotubes synthesis—review. DOI: : https://doi.org/10.1039/c1jm12254a  Applications of carbon nanotubes It is well known that CNTs are intrinsically composed of pure carbon atoms that arrange and interact with each other by the strong sp2 carbon-carbon chemical bonds and form the unique geometric structure of a carbon network; this gives CNTs fascinating and attractive properties, such as electronic, mechanical, and thermal properties. Sandeep Kumar et al. Carbon nanotubes: a novel material for multifaceted applications in human healthcare. DOI: https://doi.org/10.1039/C6CS00517A Meijo Nano Carbon Co. http://www.meijo-nano.com/en/applications/use.html