2. what is ânanoâ technology
⢠A technology that measures ,manipulate
or incorporate materials or features with
a critical dimension between 1 â 100 nm,
also whose application exploit properties
distinct from bulk macroscopic systems
from which they arise.
Nanotechnology
3. ď˝ Nano particles are particles which lie in
dimensions between 1 â 100 nm.
ď˝ âNanoâ derived from the Greek word ânanosâ
which means dwarf or extremely small.
ď˝ It can be used as a prefix for any unit to mean a
billionth of that unit.
ď˝ For example ,nanosecond (billionth of a
second),nanoliter(billionth of a
liter),nanometer(billionth of a meter)
4. ď˝ They consist of micro molecular
materials in which the active
ingredients(drug or biologically
active material)is dissolved ,
entrapped, encapsulated,
adsorbed or attached.
8. ď Top ⨠Down:
⢠Building what you want by
assembling it from building blocks
( such as atoms and molecules).
⢠Atom-by-atom, molecule-by-
molecule, or cluster-by-cluster
ď Bottom ⨠Up:
⢠Start with the bulk material and
âcut away materialâ to make the
what you want
9. ď˝ Nanoparticles may be created using several
methods. The methods of creation include Attrition
and Pyrolysis.
ď˝ While some methods are bottoms up, some are
called top down.
ď˝ Top down methods involve breaking the larger
materials into Nanoparticles.
10. ď˝ Attrition methods include methods by which
macro or micro scale particles are ground in a
ball mill, a planetary ball mill, or other size
reducing mechanism. The resulting particles are
air classified to recover Nanoparticles.
ď˝ Involves mechanical thermal cycles
⌠broad size distribution (10-1000 nm)
⌠varied particle shape or geometry
⌠Impurities
11. ď˝ Nanocomposite: A nanocomposite is a multiphase solid material
where one of the phases has one, two or three dimensions of less
than 100 nanometers (nm), or structures having Nano-scale repeat
distances between the different phases that make up the material.
This schematic shows a silicon-
carbon nanocomposite granule
formed through a hierarchical
bottom-up assembly process.
Annealed carbon black particles
are coated by silicon nanoparticles
and then assembled into rigid
spheres with open interconnected
internal channels.
12. This scanning electron micrograph shows carbon-coated
silicon nanoparticles on the surface of the composite
granules.
13. ď˝ Producing batteries with greater power output.
Researchers have developed a method to make anodes
for lithium ion batteries from a composite formed with
silicon nanospheres and carbon Nanoparticles. The
anodes made of the silicon-carbon nanocomposite make
closer contact with the lithium electrolyte, which allows
faster charging or discharging of power.
14. ď˝ In Pyrolysis, a vapors precursor (liquid or gas) is forced
through a hole or opening at high pressure and burned.
ď˝ The resulting solid is air classified to recover oxide
particles from by-product gases.
ď˝ Pyrolysis often results in aggregates and agglomerates
rather than singleton primary particles.
ď˝ Instead of gas, thermal plasma can also deliver the energy
necessary to cause evaporation of small micrometer size
particles. The thermal plasma temperatures are in the order
of 10,000 K, so that solid powder easily evaporates.
Nanoparticles are formed upon cooling while exiting the
plasma region.
15. ď˝ For example, silica sand can be vaporized with an
arc plasma at atmospheric pressure. The resulting
mixture of plasma gas and silica vapour can be
rapidly cooled by quenching with oxygen, thus
ensuring the quality of the fumed silica produced.
ď˝ The advantages of vapor phase Pyrolysis include
it being a simple process, cost effective, a
continuous operation with high yield.
16. ď˝ The liquid phase fabrication entails a wet chemistry
route.
Methods are:
o Solvothermal Methods (e.g. hydrothermal)
o Sol-Gel Methods
o Synthesis in Structure Media (e.g., microemulsion)
o Effectiveness of Solvothermal Methods and Sol-gel
methods demands a simple process, low cost,
continuous operation and high yield.
17. Solvothermal process:
Precursors are dissolved in hot solvents (e.g., n-
butyl alcohol).Solvent other than water can
provide milder and friendlier reaction conditions .If
the solvent is water then the process is referred to
as hydrothermal method.
Solvothermal synthesis has been used in laboratory
to make nanostructured titanium dioxide,
graphene, carbon nanotubes and other materials.
18.
19. ď˝ The sol-gel process is a wet-chemical technique that uses either a chemical solution
(short for solution) or colloidal particles ( nanoscale particle) to produce an integrated
network (gel).
ď˝ Metal alkoxides and metal chlorides are typical precursors. They undergo hydrolysis
and polycondensation reactions to form a colloid, a system composed of
nanoparticles dispersed in a solvent. The sol evolves then towards the formation of
an inorganic continuous network containing a liquid phase (gel).
ď˝ Formation of a metal oxide involves connecting the metal centers with oxo (M-O-M)
or hydroxo (M-OH-M) bridges, therefore generating metal-oxo or metal-hydroxo
polymers in solution.
ď˝ After a drying process, the liquid phase is removed from the gel. Then, a thermal
treatment (calcination) may be performed in order to favor further polycondensation
and enhance mechanical properties.
20. Microemulsions are clear, stable, isotropic liquid mixtures
of oil, water and surfactant, frequently in combination with
a cosurfactant.
The aqueous phase may contain salt(s) and/or other
ingredients, and the "oil" may actually be a complex
mixture of different hydrocarbons and olefins.
The two basic types of microemulsions are direct (oil
dispersed in water, o/w) and reversed (water dispersed in
oil, w/o).
Nanosized CdS-sensitized TiO2
crystalline photocatalyst prepared by
microemulsion. (Yu, J. C. et al. Chem.
Commun. 2003, 1552.)
21. 1. Lewis, L. N. Chem. Rev. (Washington, D.C.) 1993,
93, 2693.
2. Colvin, V. L.; Schlamp, M. C.; Alivisatos, A. P.
Nature 1994, 370, 354.
3. Nanoparticles, Gunter Schmidt Edition, Wiley-VCH,
2004.
4. Hirai, H.; Toshima, N. Tailored Metal Catalysts;
Iwasawa, Y., Ed.; D. Reidel: Dordrecht, 1986; pp
87-140.
5. Teranishi and M. Miyake, Chem. Mater. 1998, 10,
594-600
6. Nanoparticles - L. Anthony and P. Moghe
22. ď˝ Scientists reveal new insights on nano 3D
printing(12 Nov 2012)
A team of physicists funded by FEI
Company and the Australian
Research Council have unveiled
new physics behind the
nanofabrication technique known
as electron beam induced
deposition (EBID), essentially 3D
printing at the molecular level.
23. ď˝ Using the UTS FEI laboratory and an advanced
research grade electron microscope the scientists
have been able to explain the nature of chemical
reactions on hot, solid surfaces and to "write" highly
pure nanostructures.
ď˝ The UTS experiments have led to the discovery that
the EBID technique performs optimally under
conditions previously dismissed as ineffective, due to
gaps in prior understanding of the basic science
behind EBID. These findings help advance the
techniques and build the machines used to advance
nano scale science and technology.
25. 1. Lewis, L. N. Chem. Rev. (Washington, D.C.) 1993,
93, 2693.
2. Colvin, V. L.; Schlamp, M. C.; Alivisatos, A. P.
Nature 1994, 370, 354.
3. Nanoparticles, Gunter Schmidt Edition, Wiley-VCH,
2004.
4. Hirai, H.; Toshima, N. Tailored Metal Catalysts;
Iwasawa, Y., Ed.; D. Reidel: Dordrecht, 1986; pp
87-140.
5. Teranishi and M. Miyake, Chem. Mater. 1998, 10,
594-600
6. Nanoparticles - L. Anthony and P. Moghe
26. ⢠Techniques for the manipulation of matter at the
nano scale, 12 Nov 2012,UTS News room,
http://www.newsroom.uts.edu.au/news/2012/11/sci
entists-reveal-new-insights-on-nano-3d-printing