Transcript NanoParticles - Noadswood Science

NanoParticles
L.O: To understand what
nanoscience is, and be able to
evaluate nanomaterials
http://htwins.net/scale/
What do you think nanoscience and nanoparticles
are?
• Nanoscience is the study of phenomena
(science and structures) on a nanometer scale
(1-100nm).
• Nanoparticles are tiny manufactured structures
only a few hundred atoms
• A nanometer is a tiny unit of measurement at
about 1/1,000,000,000 metres
• A nanoparticle is a tiny manufactured structure of a few
hundred atoms, from 1 to about 100 nanometres long. (A
human hair is about 100 000 nanometres wide.)
Nanoparticles are made from carbon, metals and metal
compounds
• The properties of nanoparticles are different to the
properties of materials in bulk.
• The atoms in nanoparticles are regularly arranged in
hollow structures such as tubes and spheres one atom
thick. Being so small, nanoparticles have a very high
surface area to volume ratio.
• Nanoparticles are being made into
- tiny capsules containing drugs
- biosensors detecting toxins
•
Future designs include
- processing information in computers
- new materials harder, lighter and stronger
- Catalysts
- new coatings
- highly selective sensors
- stronger and lighter construction materials
But concerns are that they could pass through the body
undetected and the effects are unknown
Nanocoating could eliminate
foggy windows and lenses
“The coatings consist of alternating layers of silica nanoparticles, which are
basically tiny particles of glass, and a polymer called polyallylamine
hydrochloride, both of which are relatively cheap to manufacture”
“When fogging occurs, thousands of tiny water droplets condense on glass
and other surfaces. The droplets scatter light in random patterns, causing
the surfaces to become translucent or foggy. This often occurs when a cold
surface suddenly comes into contact with warm, moist air.”
“The new coating prevents this process from occurring, primarily through its
super-hydrophilic, or water-loving, nature, Rubner says. The nanoparticles
in the coating strongly attract the water droplets and force them to form
much smaller contact angles with the surface. As a result, the droplets
flatten and merge into a uniform, transparent sheet rather than forming
countless individual light-scattering spheres. “
August 29, 2005
Air-purifying Church Windows Were Early Nanotechnology
“ScienceDaily (Aug. 25, 2008) — Stained glass windows that are
painted with gold purify the air when they are lit up by sunlight, a
team of Queensland University of Technology experts have
discovered.”
Nanoparticles Boost Solar Cell Efficiency by 60%
“In experiments where silicon nanoparticles were applied on top of
solar cells, researchers observed large voltage enhancements with
dramatic increases in power ranging from as much as 60-70% in the
ultraviolet-blue (UV) range, and further reported a significant boost
in power by as much as 10% in the visible light range.”
Are nanotechnologies safe?
• Most current and future nantotechnologies, such computer chips
and catalysts, pose no new health or safety risks. This is because
the nanomaterial is fixed or etched onto a larger object and therefore
unable to stray into the environment.
• But concerns do exist about the possible impacts of manufactured
nanoparticles and nanotubes that are free to move around rather
than being fixed or embedded into a bulk material. Although these
represent just a tiny fraction of all nanotechnologies, there is some
evidence that their small size may increase any potential toxicity.
Certainly, the toxicity of a material in larger form doesnt tell us what
its toxicity will be when it is nanosized.
• The worry is that free nanoparticles could be inhaled, ingested or
enter the body via the skin, and then cause damage to cells.
Nanotubes, for example, are structurally similar to asbestos fibres,
which can cause respiratory problems when inhaled in large
amounts over long periods.
Nanoscience debate activity
• nanoscience
http://news.bbc.co.uk/1/hi/technology/73964
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