Nanoparticles
Key Stage 4
Meaning
Nanoparticles are small clumps of atoms which are between 1 and 100 nanometres (billionths of a metre) in length, width or height.
About Nanoparticles
- A Hydrogen atom has a radius of 0.1nanometres so 10 Hydrogen atoms lined up can make one nanometre. A nanoparticle may have a width of as little as 10 atoms or as many as 1000 atoms. (NB Hydrogen is being used as a comparison for the width and most nanoparticles are made of other types of atom.)
- A substance that is broken down into nanoparticles may have very different properties to large volumes of the substance.
- The surface area to volume ratio of nanoparticles is much higher than large volumes of the same substance. It is this large surface area compared to the volume that gives it the different properties.
- In 'bulk' materials a very small proportion of atoms exist on the surface of the material. However, for nanoparticles a much larger proportion of atoms exist on the surface allowing those particles to interact with others around it.
Risks of Nanoparticles
- Inhaling nanoparticles may damage the lungs. Recent research has suggested Carbon Nanotubes may be harmful if inhaled.
- Nanoparticles of certain reactive metals react very quickly with Oxygen due to their large Surface Area which could result in an explosion if ignited.
Examples
- Zinc Oxide - Nanoparticles of Zinc Oxide are used in sunscreen to absorb Ultra-violet light. Zinc Oxide normally forms a white powder, but nanoparticles of Zinc Oxide are smaller enough not to for a white layer over the skin.
- Silver - Nanoparticles of Silver can prevent the growth of Micro-organisms.
- Catalysts - Nanoparticles of Catalysts are far more efficient than larger particles due to their very large surface area.
- Nanocages - A nanocage made of Carbon in the form of a fullerene or a Carbon Nanotube can contain a drug so it can be delivered to the right location in the body.