nanomaterial

1. Synthesis Of Nanomaterial
PRESENTED BY
ABDUL LATIF
MS NATURAL SCIENCE

2. NANOTECHNOLOGY
Nanotechnology is the technology for design, fabrication and manipulation of
nanometre scale systems, in the scale of 1-100 nm

3. HOW SMALL IS NANO ?
1 µm= one millionth of a meter
1 nm= one billionth of a meter
≈ 1/50,000 thickness of a hair!
≈ a string of 3 atoms
If we shrunk all distances by 110,000,000,000 X
The sun and earth would be separated by 1 m
A football field would be 1 nm
Human hair thickness ~ 50 µm
110,000,000 km
110 m

4. PROPERTIES OF NANOMATERIALS
Enhanced electrical and heat conductivity
Increased strength, tensile properties
Magnetic properties
Optical properties – color changes with size

5. SOLVOTHERMAL METHOD
PHOTOCHEMICAL METHOD
ELECTROCHEMICAL METHOD

6. SOLVOTHERMAL METHOD

7. HISTORY:
Solvothermal synthesis route was first proposed by YI-TAI QIAN
in 1996 from university science and technology of china.
This method is very similar to Hydrothermal route, the only
difference in the precursor solution is usually No aqueous but this
not always in the case in literature uses of the expression.
SOLVO -- THERMAL
Solvant -- use of the temperature

8. SOLVOTHERMAL PROCESSES:
A “solvothermal reaction can be defined as a chemical reaction (or a
transformation) between precursor(s) in a solvent (in a close
system) at a temperature higher than the boiling temperature of
this solvent and under high pressure”.
 autogeneous pressure or imposed pressure.
 Subcritical or supercritical domain.
 Homogeneous or heterogeneous system.

9. MAIN FACTORS OF THE SOLVOTHERMAL CRYSTAL GROWTH
CHEMICAL FACTORS
PHYSICAL FACTORS
KINETICAL FACTORS
- nature of the solvant,
- nature of the nutrient,
- nature of the seeds,
- the interactions solvant/ wall of the HP. Vessel
- the Crystal growth temperature (Tgrowth),
- the T value,
- the pressure value,
- the hydrodynamics in the crystal-growth system.
- the kinetics of dissolution,
- the kinetics characterizing the diffusion of chemical species,
- the crystal growth kinetics,
- the duration of the crystal growth.

10. 10
THE SOLVOTHERMAL PROCESSES AND
THE CRYSTAL GROWTH AT THE NANOSCALE
Schematic illustrations of the different strategies for achieving 1D growth.
A)  Induction of 1D morphology through the
anisotropic structure,
B)  confinement by a liquid droplet in the
liquid/solid process,
C)  use of templates,
D)  use of capping agents able to modify the
growth rate in one direction,
E)  self assembly of OD nanostructure,
F)  size reduction of 1D microstructure.

11. Autoclave for solovothermal
Apparatus in Solvothermal Synthesis

12. Apparatus in Solvothermal Synthesis
whole apparatus part of chamber components of chamber

13. PHOTOCHEMICAL METHOD

14. PHOTOCHEMICAL METHOD
• Photochemistry is the branch of chemistry concerned with the chemical
effects of light. Generally, this term is used to describe a chemical reaction
caused by absorption.
• Photochemical reactions require a light source that
emits wavelengths.
Ultraviolet (wavelength from 100 to 400 nm)
Visible light (400 – 750 nm)
Infrared radiation (750 – 2500 nm)

15. Sources of Photochemical
In the early experiments sunlight was the light source.
Mercury vapor lamps
Low pressure mercury vapor lamps (254 nm)
Laser beams
LEDs have a relatively narrowband
Rayonet lamps
Poly chromatic sources
Monochromatic Source
The emitted light must of course reach the targeted functional group

16. • The solvent is an important experimental parameter.
• Chlorinated solvents are avoided because the C-Cl bond can lead to chlorination of the
substrate.
• Strongly absorbing solvents prevent photons from reaching the substrate.
• Hydrocarbon solvents absorb only at short wavelengths and these preferred for
Photochemical.
• Experiments requiring high energy photons.
• Solvents containing unsaturation absorb at longer wavelengths and can usefully filter out
short wavelengths.
Solvents:

18. ELECTROCHEMICAL METHOD

19.  It is possible to control particle size by adjusting the electrolysis
parameters and to improve homogeneity of Ag NPs by changing the
composition of the electrolytic solution.
 polyvinyl pyrrolid (PVP) as a stabilizing agent can be used to protect
Ag NPs from agglomeration, significantly reduces silver deposition
rate and promotes silver nucleation & Ag NPs formation rate.
ELECTROCHEMICAL METHOD

20. Electrochemical method for synthesis of Ag NPs

21.  The rate of reaction was found to increase with:
– Decrease in the distance between the electrodes (1–2 cm)
– Increase in the voltage (5–50 V DC)
– Increase in the temperature
 A longer reaction time resulted in:
– Larger size of Ag NPs
– Higher concentration of Ag NPs

22.  Alternatively, the cathode could be other metals such as
platinum.
 The presence of PVA (1–100 ppm):
– Acts as supporting electrolyte
– Accelerates the NP nucleation and growth
– Produces highly concentrated suspensions of NPs

23. THANK YOU