Nano Materials

This blog page can be used for a last minute revision on the topic of 'Nano materials' from the material science course.

Nano materials

- The scientific notation for the prefix nano is 1 x 10^-9 

- It is equal to the one-billionth of a meter .

- Nanomaterials are very small in size , having at least one  dimension of 100 nm and below .

 Examples of objects on a nanometer scale 

- Virus ( 50nm)

- DNA (2.5 nm )

Properties of Nano materials

- Materials at the nanoscale have unusual physical , chemical and biological properties.

- Nanomaterials are stronger and have different magnetic properties compared to the  other various  forms , sizes or the same material.

- Nanomaterials are really good conductors of heat and electricity .

- Nanomaterials are more chemically reactive  , reflect light better and also the colour varies when their size or the structure is being modified.

What is so great about Nanoscale ?

Surface effects

- Nanomaterials have a larger surface area compared to other similar masses of large scale materials.

- 1cm³  of the cubic nanoparticles will have total-surface area one third larger than a football field. When the surface area of the material increases, a larger amount of material can come in contact with the surrounding materials . This leads to affecting the reactivity of the material.

Surface-area-to-volume (SAV) ratio

'a' represents each side of cube length 

- Surface Area of the Cube of length a = 6a²

- Volume of the cube = a³

- Thus the SAV ratio will be 6/a

 - The SAV ratio of a cube increases  when the dimensions of the cube increases .

- The S.I Unit for SAV ratio is m^-1

- There will be a higher SAV ratio under the nanoscale when compared to the corresponding ratio at the macroscale.

- A heavy material that is being subdivided into a group of individual nanomaterials , the total will remain the same but the total surface area will be largely increased .

Colour

- The changes in colour are due to the various manner in which the photons interacts with the nanomaterials when compared to other materials.

Reactivity

Can drinks made up of aluminium

-  Aluminium is being used to make can drinks.

-  At the nanoscale , the aluminium particles are very reactive and thus will explode.

- When the surface area of the aluminium increases , the size of the aluminiun will decrease . A larger    amount of aluminum will come in contact with surrounding materials  , hence making the material      very reactive.

Electrical Conductivity

Carbon nanotubes

- Carbon nanotubes possesses a high electrical conductivity .

- The reason for the possession of high electrical conductivity is because of the unique cylindrical nanostructure of the carbon nanotubes.

Quantum Effects

What are quantum effects ?

- When the material is at the nanoscale , it's properties will vary drastically . These changes are known as quantum effects.

- When the particle size is at nanoscale range , it's properties such as colour , mechanical strength , electrical conductivity and reactivity  change as a function of the size of the particle.

- Scientists can make small adjustments to a nano material's property of interest such as colour , mechanical strength by changing the size of the material.

Applications of Nanomaterials

-  Zinc oxide nanoparticles dispersed in industrial coatings in order to protect wood, textiles from exposure to UV rays
- Miniaturised electrodes for biosensors