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/7396486.stm

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