1. NANOCHEMISTRY

2. Nanomaterials Some important terms
materials having size between 1 – 100 nm

3. Deals with synthesis and characterization of materials at nano scale.
Nanochemistry
Deals with synthesis and characterization of materials at nano scale.

4. Nanotechnology
The study of design, production, characterization and application of nano materials

5. Classification of Nanomaterials - Based of dimensions
1D – It has only one parameter either length (or) breadth (or) height Eg. Film, sheet, surface coatings 2D – it has only length and breadth Eg.nano tube, nanowire

6. 3D – it has all parameter of length, breadth and height
Eg. Nanoparticles, nanoprecipitates, nanocluster, nanocolloids

7. Nanorods

8. Nanowires

9. D/W nanorods and nanowires
distinguished on the basis of aspect ratio.
length of nanomaterial
Aspect ratio =
width of nanomaterial

10. Nanorod aspect ratio = 1 to 20 and material being 10-100 nm
Nanorod aspect ratio = 1 to 20 and material being nm. Nanowire aspect ratio greater than 20 and material being nm.

11. Synthesis of Nanomaterials
(Small to big method)
(Big to small method)

12. (Small to big method)
(Big to small method)

13. Bottom-up nanofabrication
Small to big method: atoms or molecules nanoparticle Eg. Chemical vapour deposition, sol-gel process, chemical reduction

14. Top-down nanofabrication
Larger structures nanoparticles
Eg. Lithography, ball milling

16. Characterizing Tools - Nanomaterials
SEM (scanning electron microscope)
TEM (Transmission electron microscope)
STM (scanning tunneling microscope)
AFM (Atomic force microscope)

18. Reduced Melting Point
Eg)
M.Pt. of Bulk Gold is 1064oC
M.Pt. of nano Gold is 300oC.

19. Melting Point
The melting point decreases dramatically as the particle size gets below 5 nm
Source: Nanoscale Materials in Chemistry, Wiley, 2001

20. 2. Optical properties
Nano particles show different optical properties from that of bulk materials

22. Band gap
The band gap is increases with reducing the size of the particles

23. ii) Cadmium sulphide (CdS) in bulk appears as red, but 6nm CdS is orange, 4nm CdS shows yellow and 2nm size appears as white.

24. Optical Properties Example: Zinc Oxide (ZnO)
Bulk ZnO particles
Block UV light
Scatter visible light
Appear white
Nano ZnO particles
don’t scatter visible light
Appear clear
Application to sunscreen
Nanoscale ZnO sunscreen is clear
“Traditional” ZnO sunscreen is white
Zinc oxide nanoparticles

25. optical absorption peak of nano particles

26. Magnetic Properties:
Ferro magnetic behaviour (Uniform orientation) of bulk changes to super paramagnetism (Random orientation).

27. 4. Mechanical Properties:
Nanomaterials are having high flexibility.
Flexibility is measured by Young’s modulus.
Their Young’s modulus is 10 times greater than that of steel.
iv) Due to less defects in nano materials, the mechanical strength is improved.

28. Increased Internal Perfection

29. Electrical properties
Conductivity decreases with reduced dimension due to increased surface scattering and decreased delocalization.

30. 6. Chemical Properties:
water resistance, chemical resistance and corrosion resistance are improved.
Increased total surface area
Increased number of atoms on the surface
Increased catalytic activity

31. a) For converting Nickel oxide to nickel
So, they are acting as very good catalyst compared with their bulk materials.
Eg) CNT
a) For converting Nickel oxide to nickel
b) For converting Aluminum chloride to Aluminium
1 x 10-5
7.5 x 10-6
5 x 10-6
2.5 x 10-6
1 x 10-6
Reaction rate

32. Bulk Nickel 12 reactive sides 9 x 4 = 36 Reactive sides
Nano nickel particles 12 11 10 Ni Ni Ni 4 5 6 1
After size reduction 4 Ni Ni Ni Ni 2 3 Ni Ni Ni
12 reactive sides
9 x 4 = 36 Reactive sides

33. 7. Surface properties
The total surface area (or) the number of surface atom increases with reducing size of the particles

35. Thank You