Nanotechnology lecture2

NANOTECHNOLOGY

NANOTECHNOLOGY: Prof. Ninad Mehendale

What we learnt last time2017Prof. Ninad Mehendale2

What we learnt last time2017Prof. Ninad Mehendale3

Whatever happened2017Prof. Ninad Mehendale4Show must go on !!!

What is Carbon 2017Prof. Ninad Mehendale5Carbon is a chemical element with symbol C and atomic number 6. It is nonmetallic and tetravalent making four electrons available to form covalent chemical bonds.

Carbon products2017Prof. Ninad Mehendale6







Diamond is a metastable allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at standard conditions.


Diamond has a wide bandgap of 5.5 eV corresponding to the deep ultraviolet wavelength of 225 nanometers. This means pure diamond should transmit visible light and appear as a clear colorless crystal. Colors in diamond originate from lattice defects and impurities.








What is fullerene. 2017Prof. Ninad Mehendale19a form of carbon having a large spheroidal molecule consisting of a hollow cage of sixty or more atoms, of which buckminsterfullerene was the first known example. Fullerenes are produced chiefly by the action of an arc discharge between carbon electrodes in an inert atmosphere.

What is fullerene. 2017Prof. Ninad Mehendale20Fullerenes consist of 20 hexagonal and 12 pentagonal rings as the basis of a closed cage structure .

What is fullerene. 2017Prof. Ninad Mehendale21

What is C60. 2017Prof. Ninad Mehendale22

Buckminsterfullerene (or Bucky-ball) is a spherical fullerene molecule with the formula C60. It has a cage-like fused-ring structure (truncated icosahedron) which resembles a football (soccer ball), made of twenty hexagons and twelve pentagons, with a carbon atom at each vertex of each polygon and a bond along each polygon edge.

What is C60. 2017Prof. Ninad Mehendale23

High-vacuum electrolysis of a C60-fullerene derivative. Slow diffusion into the anode (right side) yields the characteristic purple color of pure C60.

What is alternative to C60. 2017Prof. Ninad Mehendale24

Types of compounds of fullerenes2017Prof. Ninad Mehendale25Compounds of fullerenes may be classed according to two different categories: Exohedral (inside the cage) and Endohedral (outside the cage).

How fullerenes are formed2017Prof. Ninad Mehendale26Combustion flame synthesis

Combustion?2017Prof. Ninad Mehendale27

Combustion?2017Prof. Ninad Mehendale28The process of burning something.

Combustion?2017Prof. Ninad Mehendale29The process of burning something.Rapid chemical combination of a substance with oxygen, involving the production of heat and light.

Flame?2017Prof. Ninad Mehendale30A flame is the visible, gaseous part of a fire. It is caused by a highly exothermic reaction taking place in a thin zone. Very hot flames are hot enough to have ionized gaseous components of sufficient density to be considered plasma.

Flame colors?2017Prof. Ninad Mehendale31Temperature

Flame colors?2017Prof. Ninad Mehendale32Color tells us about the temperature of a candle flame. The inner core of the candle flame is light blue, with a temperature of around 1670 K (1400 C). That is the hottest part of the flame. The color inside the flame becomes yellow, orange, and finally red. The further you reach from the center of the flame, the lower the temperature will be. The red portion is around 1070 K (800 C).

Flame colors?2017Prof. Ninad Mehendale33TemperatureFuel

Flame colors?2017Prof. Ninad Mehendale34TemperatureFuel

What is combustion flame synthesis2017Prof. Ninad Mehendale35









Q.1 Explain combustion flame synthesis [10M]2017Prof. Ninad Mehendale44

How fullerenes are formed2017Prof. Ninad Mehendale45Combustion flame synthesisCrystal formation

What is Crystal?2017Prof. Ninad Mehendale46A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.Examples of large crystals include snowflakes, diamonds, and table salt.

What is Crystal?2017Prof. Ninad Mehendale47A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.Examples of large crystals include snowflakes, diamonds, and table salt.

Q. 2 Explain in detail process of crystal formation for fullerene production? [5M]2017Prof. Ninad Mehendale48

Education

Nanotechnology lecture2