about nano particles
Published on: Mar 3, 2016
Transcripts - Nano properties
1.Carbon Nano TubesCarbon nano tubes were first discovered by sumio lijima in1991. CNT’s are extended tubes of grapheme sheets;There are two types of CNT’s: a) single-walled b) multi-walled. Single walled is 1nm of diameter and Multi walled is 10nm of diameter. These tubes are capable of storing hydrogen gas in fuel- cell in car.These tubes are 100 times stronger than steel. They can hold 8% by weight of hydrogen. In cars instead of keeping large tanks for gas we use nano tubes for storing hydrogen gas. These are efficiently used for this purpose. Carbon nano tubes are large molecules of pure carbon that are made of thin,long and thousands of nano meters long. Carbon nano tubes are made of laser evaporation method. In this method, graphite and nickel catalyst and heated upto 1200 degrees centigrade and then the material is irradiated with laser. Properties: • They are highly elastic and can withstand structural distortions. • They are resistant to attack by chemicals and oxygen. • They are extremely light in weight. Single walled has density of 0.8 g/cc and Multi walled has density of 1.8g/cc. • Due to presence of c-c bond, they possess remarkable strength. ELECTRICAL PROPERTIES: They vary between semi-conducting to metallic depending on diameter and chirality of the tube.
MECHANIOCAL PROPERTIES: These are quiet unique. 2.Fullerenes In the mid-1980s a new class of carbon material wasdiscovered called carbon-60. These are spherical moleculesabout inm of diameter, comprising of 60 carbon atomsarranged as 20 hexagons and 12 pentagons.