Carbon Nanotubes And Its Applications 2

Cathode-Ray Lighting Elements •Carbon nano materials- field emitters. •Triod type design.

•Early models – Cylindrical rods with MWNTs were cut in thin disks and were glued to stainless steel plates by silv paste.

•Later models – Nano tubes are screen printed on to th metal plates.

•Luminance of phosphor screen – 6.4 * 104 cd / cm2 f

Flat Panel Display

•Demonstration structure constructed at Northwester University •Nanotube-epoxy stripes on the cathode glass plate •Phosphor-coated Indium-Tin-Oxide (ITO) stripes on the anode plate

•Pixels are formed at the intersection of cathode an anode stripes. At a cathode-anode gap distance of 30 µm, 230 current density.

•Half-voltage off-pixel scheme. Pulses of ±150V are switched among anode and cathode stripes, •Samsung has fabricated 4.5-inch diode-type field emission display with SWNT stripes on the cathode and phosphor-coated ITO stripes on the anode. •SWNTs synthesized by the arc-discharge method were dispersed in isopropyl alcohol and then mixed with an organic mixture of nitro cellulose. •Paste was squeezed into soda lime glasses through a

Energy Storage Applications •Graphite, carbonaceous materials and carbon fiber electrodes have been used for decades in fuel cells, battery and several other electrochemical applications. •Efficiency of fuel cells and this depends on various factors, such as the structure and morphology of the carbon material used in the electrodes.   •The electron transfer kinetics take place fastest on nanotubes than in conventional carbon electrodes.

Hydrogen Storage

•Metal hydrides and cryo-adsorption are the tw commonly used means to store hydrogen, typically at high pressure and/or low temperature. In metal hydrides, hydrogen reversibly stored in the interstitial sites of the host lattice.

•Hydrogen can also be stored in the gas phase in th metal hydrides.   •Because of their cylindrical and hollow geometry, and nanometer-scale diameters, it has been predicted tha the carbon nanotubes can store liquid and gas in the inne

•Higher hydrogen uptake, up to 14–20wt%, at 20–400° under ambient pressure was reported in alkali meta intercalated carbon nanotubes.

  •Many experiments are performed on SWNT containin materials.Still it is not clear whether carbon nanotubes will have real technological applications in the hydrogen storag application area.

  •Carbon nanotubes readily absorb other gaseous species

Filled composites •Carbon fibers have 50 times the specific strength of steel. •They are excellent load bearing reinforcements in composites – due to their high strength. •Use of SWNT is preferred to MWNTs in composites.

•Nanotubes sustain large strains (40%) in tension withou showing the • Nanotube filled ceramics withstand high temperature. signs of fracture. •Using Nanotubes for structural polymer composites increases the toughness of the composites by absorbing energy during their highly flexible elastic behavior.