Presentation on theme: "Materials CNT. History 1991 Discovery of multi-wall carbon nanotubes 1992 Conductivity of carbon nanotubes 1993 Structural rigidity of carbon nanotubes."— Presentation transcript:
History 1991 Discovery of multi-wall carbon nanotubes 1992 Conductivity of carbon nanotubes 1993 Structural rigidity of carbon nanotubes 1993 Synthesis of single-wall nanotubes 1995 Nanotubes as field emitters 1996 Ropes of single-wall nanotubes 1997 Quantum conductance of carbon nanotubes 1997 Hydrogen storage in nanotubes 1998 Chemical Vapor Deposition synthesis of aligned nanotube films 1998 Synthesis of nanotube peapods 2000 Thermal conductivity of nanotubes 2000 Macroscopically aligned nanotubes 2001 Integration of carbon nanotubes for logic circuits 2001 Intrinsic superconductivity of carbon nanotubes
Potential Applications Tips for Atomic Force Microscopy Cells for hydrogen storage Nanotransistors Electrodes for electromechemical applications Sensors of biological molecules Catalysts Reinforcement of composite materials Semiconductor or metallic conductive nanomaterials Various aerospace applications
Potential Applications Reinforcement within a polymeric matrix Outstanding mechanical properties – High Young’s modulus – Stiffness and flexibility – Unique electronic properties – High thermal stability The nearly perfect structure of CNTs, their small diameter, and their high surface area and high aspect ratio, provide an amazing inorganic structure with unique properties extremely attractive to reinforcing organic polymers
Potential Applications Flat Panel Displays – Prototypes have been made by Samsung Gas-Discharge Tubes in Telecom Networks Energy Storage Electrochemical Intercalation of Carbon Nanotubes with Lithium – CNTs can be used as the cathode to make a battery hold 3x as much charge and output 10x as much power Nanoprobes and Sensors
Potential Applications Use as coatings – Antistatic coatings – Flame barrier coatings – Fouling release coatings On boats to prevent marine life from adhering to the ship’s bottom
BMC bicycle frame made of nanotube-reinforced resin, 2005 Tour de France. ARKEMA belongs to the network of partners.
Potential Applications Markets EnergyElectronicsAutomotive Stuctural CompositesOthers BatteryWind Semicon and Disk Drive ITO replacement Electrostatic painting Fuel systemsAerospace Sporting goods Thermal Management Flame Retardant CNT Performance Attribute High electrical conductivityX XXXXX High thermal conductivityX X XX High tensile strengthXX XX High elasticity X XX High absorbency X X XX High aspect ratio (L/D)XXXXXXXXXX Low weight X XXXX
Properties When small quantities of nanotubes are incorporated into the polymer, the electrical, optical and mechanical properties improve significantly CNTs in large amounts form clusters, diminishing their interaction The Young’s modulus of the multi-walled carbon nanotubes is 0 ⋅ 9 TPa
Physical Properties of Carbon Nanotubes Below is a compilation of research results from scientists all over the world. All values are for Single Wall Carbon Nanotubes (SWNT's) unless otherwise stated. Equilibrium Structure Average Diameter of SWNT's nm Distance from opposite Carbon Atoms (Line 1) 2.83 Å Analogous Carbon Atom Separation (Line 2) Å Parallel Carbon Bond Separation (Line 3) 2.45 Å Carbon Bond Length (Line 4) 1.42 Å C - C Tight Bonding Overlap Energy ~ 2.5 eV Group Symmetry (10, 10) C 5V Lattice: Bundles of Ropes of Nanotubes Triangular Lattice (2D) Lattice Constant 17 Å Lattice Parameter: (10, 10) Armchair16.78 Å (17, 0) Zigzag16.52 Å (12, 6) Chiral16.52 Å Density: (10, 10) Armchair1.33 g/cm 3 (17, 0) Zigzag1.34 g/cm 3 (12, 6) Chiral1.40 g/cm 3 Interlayer Spacing: (n, n) Armchair3.38 Å (n, 0) Zigzag3.41 Å (2n, n) Chiral3.39 Å. Optical Properties Fundamental Gap: For (n, m); n-m is divisible by 3 [Metallic]0 eV For (n, m); n-m is not divisible by 3 [Semi-Conducting]~ 0.5 eV Electrical Transport Conductance Quantization (12.9 k )-1 Resistivity cm Maximum Current Density A/m 2. Thermal Transport Thermal Conductivity ~ 2000 W/m/K Phonon Mean Free Path ~ 100 nm Relaxation Time ~ s. Elastic Behavior Young's Modulus (SWNT) ~ 1 TPa Young's Modulus (MWNT) 1.28 TPa Maximum Tensile Strength ~ 100 GPa
Mechanical Properties of Engineering Fibers Fiber MaterialSpecific DensityE (TPa)Strength (GPa)Strain at Break (%) Carbon Nanotube HS Steel < 10 Carbon Fiber - PAN Carbon Fiber - Pitch E/S - glass / / Kevlar* Kevlar is a registered trademark of DuPont. Properties
Table 2. Transport Properties of Conductive Materials MaterialThermal Conductivity (W/m.k)Electrical Conductivity Carbon Nanotubes> Copper4006 x 107 Carbon Fiber - Pitch x 106 Carbon Fiber - PAN x 106 Properties
Electrical conductivity: Carbon nanotubes are conductors or semiconductors, based on coiling helicity. Their conductivity ranges from 1 S/cm to 100 S/cm. This property has been calculated and verified in experiments. Thermal conductivity: Carbon nanotubes feature thermal conductivity close to that of diamond (3000 J/K), the best thermal conductor known. Mechanical performance: In the hexagon plane, the Young’s modulus for carbon nanotubes has been theoretically evaluated at 1TPa. Together with this outstanding strength, carbon nanotubes boast high flexibility and good plasticity. Adsorption: Nanotubes were first studied with the objective of becoming a means of storing hydrogen for the new fuel cells. Although this application has been gradually discarded, the fact remains that nanotubes have an empty space around the cylinder axis which can constitute a nanotank. The specific surface of nanotubes is approximately 250 m2/g, imparting good adsorption capacity.
Properties CNTs have been shown to possess many extraordinary properties such as strength 16X that of stainless steel and with a thermal conductivity five times that of copper. aspect ratio (length over diameter) ranges from 1,000 to 1,000,000 Electrical Resistivity: Ω-cm Current Density: 10 7 amps/cm 2 Thermal Conductivity: 3,000 W/mK Tensile Strength: 30 GPa Elasticity: 1.28 TPa
Nanotube Research Articles\Overall\nanotube composites.pdf Nanotube Research Articles\Overall\nanotube composites.pdf Very good article explaining the basics of CNT’s
CNT–Polymer Interfacial Strength
Effects From Size
Additives Additives can aid in the dispersion of the CNTs
Functionalized CNTs Oxidation on the surfaces of these materials are useful moieties in order to bond new reactive chains that improve solubility, processability and compatibility with other materials and, therefore, improve the interfacial interactions of CNs with other substances The most important impact has been produced by oxidation methods which, in addition to reducing impurities, cause chemical modifications of CNTs The COOH groups generated in the oxidation process are used to attach different molecules useful to improve surface compatibility of CNTs with other materials
Functionalized CNTs The COOH groups generated in the oxidation process are used to attach different molecules useful to improve surface compatibility of CNTs with other materials Chemical functionalization has reached an important position in the CNT field, as different chemical processes have been developed to diversify CNT properties The remarkable properties obtained when f-CNTs are incorporated into polymeric composites represent a promising route to design ideal materials for aerospace related structural applications However, the field requires much deeper fundamental research
Functionalized CNTs Chemical functionalized CNTs significantly decreased the electrical conductivity of epoxy nanocomposites due to unbalance polarization effect and physical structure defects due to severe condition during acidic treatment process Non chemical functionalized CNTs are more suitable for the electrical applications Chemical functionalization of CNT is still necessary for increase dispersion quality and strengthens the interfacial bonding strength with polymer matrix, which more important in structural applications
Functionalized CNTs (Kentera)
Adhesion and reinforcement in carbon nanotube polymer composite The interfacial shear stress is found to increase linearly with the applied strain in small strain regime and a lower bound value for the shear strength is found MPa at low temperatures. Such value decreases with the increase of temperature. At large strains the interfacial bonds break successively with the shear stress decreasing in a staircase manner.
Adhesion and reinforcement in carbon nanotube polymer composite The mechanical properties of the composite are found to be largely enhancedover a wide temperature range from 50 to 350 K compared with the bulk polymer, due to the enhanced VDW interactions. The degree of increase in the Young’s modulus is around 200% for the composite in this study, and the difference with that from the continuum medium approximation based Halpin–Tsai formula suggests that interfacial atomic structure is crucial for a nanocomposite.
Adhesion and reinforcement in carbon nanotube polymer composite
PMMA Relative to pure PMMA, a 32% improvement in tensile modulus and a 28% increase in tensile strength were observed in PMMA- based nanocomposites using 1.0 wt% nanotube filler.
Epoxy no improvement in mechanical properties was observed in epoxy-based nanocomposites. The poorer mechanical performance of the latter system can be explained by a decrease of the crosslinking density of the epoxy matrix in the nanocomposites, relative to pure epoxy.
PVA To summarize, MWNTs have been well dispersed in PVA matrix through gum arabic treatment. The PVA/MWNT composite films exhibit good mechanical properties
PBT The addition of up to 0.2 wt% MWCNT to PBT induces an increase of the microhardness of about 12%. The H values obtained are much smaller than those derived from the elastic modulus using Struik’s relation. The use of SWCNT does not improve the micromechanical properties
The stress value or normally known as tensile strength has been increased to 21.0% for 1 wt% of CNTs up to 70.26% for 10 wt% of CNTs The Young’s modulus or modulus of elasticity has been increased to for 1 wt% of CNTs up to % for 10 wt% of CNTs compared to SBR without CNTs.