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Carbon NANOTUBES de carbones. La prochaine vague technologique. Table des matières. What are Carbon Nanotubes?. Properties of CNTs. Applications futures possibles. How do we produce them?. Problèmes . Références. Questions???. Qu’est-ce qu’un nanotube de carbone?. What is it?.
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Carbon NANOTUBES de carbones La prochaine vague technologique
Table des matières • What are Carbon Nanotubes? • Properties of CNTs • Applications futures possibles • How do we produce them? • Problèmes • Références • Questions???
What is it? • Iijima discovered them in 1991 • Feuille de graphite roullée en un cylindre • Liens sp2 • SWNT vs MWNT • Forces de Van der Vaals tiennent les épaisseurs ensemble. • End(s) in the shape of buckyballs
Comment les reconnaître? • Les CNTs sont identifiés par un couple d’entier (n,m)
Caractéristiques des CNTs • SWNT diameter: 0.4 to 3 nm • 100 000 times smaller than a hair • MWNT diameter: ~1.4 to 100 nm • Length: up to several millimeters at best, usually a few microns
Properties of CNTs Mechanical properties • Young’s modulus of ~1TPa for SWNT and up to 1,28TPa for MWNT • Steel is at ~0.2TPa… • Wow! • Highest tensile strength ever mesured • Bone – 130 • Steel - ~800 • Kevlar – 3620 • CNT – 63 000 -une paille qui se déplie
Properties of CNTs Electrical properties • 3cas: -armchair SWNTare metals -(n-m) divisible by 3 ar semiconductors with tiny gap -others are semiconductors with ban gap depends on (diameter)-1 • Semblable pour les MWNTs • The nanotubes conduct current ballistically (without scattering) -phonons propagate easily along a CNT -high current with virtually no heating • Superconductivity observed at low pressure (0.55K) • Expérimentalement, SWNT peut supporter jusqu’à 109A/cm2 pour un métal normal, c’est seulement ~ 105A/cm2 (vaporisation!)
Applications of CNTs (1) • Conductive and high-strength composites; • Field emission displays and radiation sources; • Lampes basée sur les nanotubes;(>8000 hours) • One-dimensional electronics • Energy storage and energy conversion devices; • Propriétés électrochimiques des CNTs permet la création de supercondensateurs • Electromechanical actuators might be used in robots…eventually
Applications of CNTs (2) • Nanometer-sized semiconductor devices • Vestes anti-balles • Média d’entreposage d’hydrogène; • Anti-earthquake buildings • Production de rayons X et micro-ondes • Supercapacitors • Cancer treatment (seen in a previous presentation)
CNT production • Laser abblation • Chemical vapor deposition • Arc discharge • Plasma torch
CNT production Carbon arc discharge • 2 carbon electrodes (3 and 4) vaporized with catalityc metal • Applied voltage causes plasma between electrodes • Arc-electrode interaction phenomena limitations
CNT production Plasma torch • Plasma torch: MegaWatt power scale in industry • Chercheur de McGill (J-L Meunier): • Possibility to size-up the system
Problems with CNTs (1) • Cost of production -high purity: 750$/g - with impurities: 60$/g • Diversité des nanotubes • No method available to effectively separate them and/or produce CNT with only one twist • Limitations expérimentales dans la production • Par exemple la vitesse d’évaporation du tungstene sur les électrodes
Problems with CNTs (2) • Méthode d’assemblage complexes pour des «réseaux» de nanotubes • Moins de problèmes avec les MWNTs • Multiton production in early 1990s • Hyperion Catalysis International Inc • In Japan, plans for 120 ton/year of MWNT at 75$/kg
Références • Physical properties of carbon nanotubes, ADAMS II, T., (2000) (http://www.pa.msu.edu/cmp/csc/ntproperties/) • Carbon nanotubes and related structures:New materials for the 21st century, HARRIS, P.J.F., Am. J. Phys, Vol 72, no.3, p.415, March 2004 • Atomic chiken wire, LOUIE, S.,(http://www.lbl.gov/wonder/louie-2.html) • Carbon nanotube, “Wikipedia”, (http://en.wikipedia.org/wiki/Carbon_nanotube) • Carbon nanotubes roll on, Physics Web, (june 2000) (http://physicsweb.org/articles/world/13/6/7/1)[novembre2005]
Références(2) • Multiwall carbon nanotubes, Physics Web, (june 2000) (http://physicsweb.org/articles/world/13/6/8/1)[novembre2005] • Carbon nanotubes from the dissociation of C2Cl4 using a dc thermal plasma torch, HARBEC D.,MEUNIER J-L., GUO L., J. Phys. D: Appl. Phys. 37, pp.232-239,2121-2126,(2004) • Fullerene synthesis in the graphite electreode arc process:local plasma characteristics and correlation with yield, Saïdane K, et al., J. Phys. D: Appl. Phys. 37, pp.232-239,(2004) • Carbon Nanotubes--the Route Toward Applications, Science, Vol 297,no.5582, pp 787-792
Questions? Maintenant c’est votre tour de parler!