Done by: Ooi xun yuan 3i319

nano-Particles nano-Technology nano-World Done by: Ooixunyuan 3i319

The world influenced by nanotechnology. • Nanotechnology is the study of very minute objects, where the size of such objects range to as small as one out of a billion meter. • 1 nanometer = 1/1,000,000,000 meter • It is also very diverse, and thus, as the word ‘nano’ suggests, it is the technology that allows scientists to control matter on the atomic scale. What is the nano-world?

Nano-particles are defined to be small objects that behave as a small unit in terms of transport and properties. They may or may not exhibit size-related properties that differ significantly from those observed in fine particles or bulk materials. Nano-particles

Their properties change together with a change in their sizes. Heating these nanoparticle arrays also introduce instability into the structures, since smaller nanoparticles start to melt first. E.g.: Using this method, a nanowire 10 times thinner than any wire, which is important in industries where appliances cannot be too big. Nano-particles

For quality-control: When objects become very small till it cannot be seen with the naked eye, it is very hard to control it. The nano-world created thus allows us to see and access these minute objects, and allows us to take control of it. E.g.: In medicine, virus are usually very small and hard to detect. Only by controlling them through the nano-world can we find ways to fight these viruses. Why Are they important?

For further research: Nano-particles are also seen to act as a bridge between bulk materials and atomic or molecular structures, generating great scientific interest. This is because particles have different properties and act differently when its size is 1 micrometer and larger (bulk materials) or 1 nanometer and smaller (atomic structures) Why are they important?

For manufacturing more applications: With nano-particles, they can be introduced into a matrix to allow an object to obtain a more accurate set of properties for certain industries For instance, nano-particles can be introduced to alter the hardness, the electrical or heat insulation of an object. Why are they important?

NANO-GOLD Examining the

Also known as colloidal gold A suspension of sub-micrometer-sized gold particles in a fluid – usually water Not gold in colour, unlike what people may think, as its reduced particles can now absorb green light, reflecting only red light and is red in colour Exhibit magnetism, unlike normal gold, which are not magnetic Aqueous nano-gold Nano-gold (properties)

Loses its inertness when shrunk to around 3nm ~ 5nm, acting as excellent catalysts If it is any bigger or smaller than that, it would regain its inertness One such reaction is the conversion of carbon-monoxide (CO) to carbon-dioxide (CO2). Nano-gold catalyzes this reaction at room temperature and with 100-percent efficiency. This can be applied to firefighting jobs, where they might have to extinguish fires which have incomplete combustions, and the catalysts help to convert the poisonous CO to CO2. Nano-gold (Properties)

Interesting discoveries have been made along the way to explain the varying properties that nano-gold has. However, none of them had been concrete enough, and can only partially explain some of the phenomena. Nano-gold (explanation)

The bond-order-length-strength (BOLS) correlation mechanism: It indicates that the broken bond induced local strain and quantum trapping and the associated densification of charge and energy in the surface skin are responsible for the size-induced behaviour. Having shorter and stronger bonds in the surface skin lowers the energy levels and increase the elecronegativity of electrons, hence atoms would take in electrons easily. This helps to explain why nano-gold are such great catalysts. Nano-gold (explanation)

Electron Microscopy: The nano-gold particles can be attached to many traditional biological probes. These particles can be manipulated and easily differentiated due to its varying properties when their sizes are changed. Hence, it can be used in electron-microscopes, where very small objects are observed. What it is used for

Health and medical applications: Used as a therapy for rheumatoid arthritis in rats. Implantation of gold beads near arthritic hip joints in dogs has been found to relieve pain. Colloidal gold can even be used to target tumours and provide detection in cancer research. What it is used for

Venturing into other nano-materials…

Allotropes of carbon with a cylindrical nanostructure. • Categorized as a fullerene: They are molecules totally composed of only carbon atoms. • Hence it is insoluble in water and in other organic solvents • About 10,000 times thinner than a human hair, but up to 18cm in length • Possesses high mechanical strength. Carbon nanotubes (properties)

In solar cells: A carbon nanotube complex can be formed from carbon nanotubes and fullerenes. The fullerenes would trap the electrons under sunlight. The nanotubes would help to allow the electrons to flow, producing electricity as a solar cell What it is used for

Paper batteries: Batteries engineered to use a paper-thin sheet of cellulose with aligned carbon nanotubes The nanotubes acts as electrodes, and allows the devices to conduct electricity. It provides a long, steady power output compared to a conventional battery, as it functions both as a lithium-ion battery and a supercapacitor. What it is used for

Bullet-proof, stab-proof clothings: With high mechanical strength, it might be able to stop bullets or knife from penetrating the body totally. However, the bullet’s kinetic energy might still cause broken bones and internal bleeding. Hence, it is still a work in progress. What it is used for

Carbon may have even more applications in other fullerene structures. Nanotubes are only one of the fullerenes that have a tube shape. Fullerenes also consist of spherical shapes, which are able to store electricity or heat. In general, they have more unusual properties chemically, physically and biologically, as showed in the nanotubes too. Carbon nanotubes (exploration)

Between 1 nm to 100 nm in size • There are many routes to synthesizing silver nanoparticles. • Physical vapour deposition • Ion implantation • The particles grow in the substrate with the bombardment of ions • Wet chemistry • Reduction of a silver salt with a reducing agent with a colloidal stabilizer Silver nanoparticles (introduction)

Medical devices: • Surgical instruments • Surgical masks • Wound dressings • Treatment of HIV-1 What it is used for

Others: • Household appliances • Samsung has created a material called “Silver Nano”, including silver nanoparticles on the surfaces of household appliances. • The cathode in a silver-oxide battery What it is used for

Chang Qing, Sun. (2008, June 27). Nanogold chemistry. Retrieved (2010, June 10) from http://www.scitopics.com/Nanogold_chemistry.html Lehigh University (2004, April 29). Nanogold Does Not Glitter, But Its Future Looks Bright. ScienceDaily. Retrieved (2010, June 10) from http://www.sciencedaily.com/releases/2004/04/040428062059.htm Luna Nanoworks (n.d.). Nanotechnology - carbon nanomaterials. Retrieved (2010, June 16) from http://www.lunananoworks.com/products/trimetaspheres.asp References

Nanomaterials. Wikipedia. Retrieved (2010, June 10) from http://en.wikipedia.org/wiki/Nanomaterials Colloidal Gold.Wikipedia. Retrieved (2010, June 10) from http://en.wikipedia.org/wiki/Colloidal_gold Carbon Nanotube.Wikipedia. Retrieved (2010, June 16) from http://en.wikipedia.org/wiki/Carbon_nanotube Silver nanoparticles.Wikipedia. Retrieved (2010, June 16) from http://en.wikipedia.org/wiki/Silver_nanoparticles References:

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Done by: Ooi xun yuan 3i319