Done by: Ooi xun yuan 3i319
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Transcript of Done by: Ooi xun yuan 3i319
DONE BY: OOI XUN YUAN 3I319
nano-Particlesnano-Technology
nano-World
WHAT IS THE NANO-WORLD? 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.
NANO-PARTICLES 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.
WHY ARE THEY IMPORTANT? 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.
EXAMINING THE NANO-GOLD
NANO-GOLD (PROPERTIES) 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 (EXPLANATION) 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.
WHAT IT IS USED FOR 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.
VENTURING INTO OTHER NANO-MATERIALS…
CARBON NANOTUBES (PROPERTIES) 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.
WHAT IT IS USED FOR 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.
CARBON NANOTUBES (EXPLORATION) 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.
SILVER NANOPARTICLES (INTRODUCTION) 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
WHAT IT IS USED FOR 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
REFERENCES 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
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