Introduction of Nanomaterials
A material with
- any external dimension in the nanoscale (size range from approximately
). - having internal structure or surface structure in the nanoscale.
At nanoscale, materials exhibit very unusual and very interesting properties. Examples: Graphene has very high young’s modulus and very high carrier mobility.
Nano-object
An object with any external dimension is in the nanoscale.
Examples: carbon nanotube, bucky ball.
Nano-structured material
A material where its internal or surface structure is in the nanoscale.
Examples:
Nano in nature
- Lotus leaves being super-hydrophobic
- Gecko adhesive system
Nano-science
Study of structures and materials on the nanoscale.
Nanotechnology
Development of materials and devices by exploiting the characteristics of particles on the nanoscale.
Applications
- Nanoscale transistors
- Higher-performance
- Improved energy efficiency
- Magnetic data storage
- High data density and data capacity
- Ultra compact
- Nano-medicine and drug delivery
- Energy storage
Preparation of nanomaterials
Top-down approach
Nanoscale dimensions are created using larger components, by externally controlled devices.
Examples: Lithography, Etching techniques.
Photolithography
Can be used to create nanoscale patterns in thin films or bulk substrates.
The steps:
- Coat
wafer with a photosensitive material.
A material which changes its properties when exposed to electromagnetic radiation - Add a mask and use an EM radiation.
- Developer solution removes either reacted or unreacted material.
- The silicon wafer is etched to transfer the pattern onto silicon wafer.
- Photosensitive material is removed.
Bottom-up approach
Molecular components arrange themselves into more complex nano materials/objects.
Examples: Molecular self-assembly, Chemical vapour deposition