Principle of nanotecnology

*Nanotechnology is science, engineering, and technology conducted at the Nano scale, which is about 1 to 100 nanometers.

*Nano science and Nano technology are the study and application of extremely small things and can be used across all the other science fields, such as chemistry, biology, physics, materials science, and engineering.

How big (small) are we talking about?

*1 meter

source: CERN http://microcosm.web.cern.ch/microcosm

*10 centimeters

source: CERN http://microcosm.web.cern.ch/microcosm

*1 centimeter

source: CERN http://microcosm.web.cern.ch/microcosm

*100 micrometers

source: CERN http://microcosm.web.cern.ch/microcosm

*10 micrometers

source: CERN http://microcosm.web.cern.ch/microcosm

*1 micrometer

source: CERN http://microcosm.web.cern.ch/microcosm

*100 nanometers

source: CERN http://microcosm.web.cern.ch/microcosm

*10 nanometers

source: CERN http://microcosm.web.cern.ch/microcosm

*1 nanometer

source: CERN http://microcosm.web.cern.ch/microcosm

*It’s not just how big you are

*It’s what you can do with it

Origins of Nanotechnology

*5th century BC Greek – Democritus

* All matter is made up of undividable particles called atoms

* There is a void, which is empty space between atoms

* Atoms are completely solid

* Atoms are homogeneous, with no internal structure

* Atoms vary in 1) Size

2) Shape

3) Weight

1) chemical elements are made of atoms

2) the atoms of an element are identical in their masses

3) atoms of different elements have different masses

4) atoms only combine in small, whole number ratios such as 1:1, 1:2, 2:3 and so on

5) atoms can be neither created nor destroyed

*Nanoparticles are the end products of a wide variety of physical, chemical and biological processes some of which are novel and radically different, others of which are quite commonplace.

*Nanoparticles may be defined as submicron (<1µm) colloidal systems, generally, but not necessarily, made of polymers (biodegradable or not).

* Advantages: Nanotechnology lets us make almost every manufactured product faster, lighter, stronger, smarter, safer and cleaner, and even more accurate. We can already see many of the possibilities as these few examples illustrate

*. Disadvantages: The biggest disadvantage is that Nanotechnology is actually VERY expensive, so not everyone can buy it or afford it. Its also very hard to create, and just a single molecule of powder or dust can damage the whole thing while it is being created/ formed.

*Nanoparticles may be created using several methods. Some of them may occur in nature as well. The methods of creation include attrition and pyrolysis. While some methods are bottoms up, some are called top down. Top down methods involve braking the larger materials into nanoparticles.

*Attrition

*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.

* Involves mechanical thermal cycles

*Yields

*broad size distribution (10-1000 nm)

*varied particle shape or geometry

* impurities

*Application

*Nanocomposites

*Nano-grained bulk materials

*Other methods such as,

*Bottoms up methods

*These are further classified according to phases:

*Gas (Vapor) Phase Fabrication: Pyrolysis, Inert Gas Condensation

Liquid Phase Fabrication: Solvothermal Reaction, Sol-gel, Micellar Structured Media

*Pyrolysis

*In pyrolysis, a vaporous precursor (liquid or gas) is forced through a hole or opening at high pressure and burned. The resulting solid is air classified to recover oxide particles from by-product gases. Pyrolysis often results in aggregates and agglomerates rather than singleton primary particles.

Where Are We Today?