NANOPARTICLES

  • Particles can be placed into one of three categories according to their diameter:
    • Coarse particles (also called particulate-matter or dust)
    • Fine particles
    • ==Nanoparticles==

The diameter in nanometres used to classify particles

  • Nanoparticles are between ^^1 and 100 nanometres^^ in size and usually ^^contain only a few hundred atoms^^

  • Atoms and simple molecules are around 100 times larger than this

  • Nanoparticles are much smaller than fine particles which have diameters of between 100 and 2500 nm

  • The research into the production and application of nanoparticles is called nanoscience

    • One of the most interesting features of nanoparticles is their very high surface area to volume ratio
    • ^^As particles decrease in size, their surface area increases in relation to their volume^^
    • ^^Fullerenes (nanoparticles made of carbon)^^ behave very differently to larger compounds of carbon like diamond and graphite
    • The surface area to volume ratio is an important feature in catalysis and surface chemistry
    • ^^The higher the ratio then the more surface area is available for reaction, hence the better the catalyst^^

    ** \n %%Exam Tip%%**

    Nanoparticles display different properties to the same element in bulk form due to their high surface area to volume ratio*** \n ***

  • Properties of Nanoparticles

    • ^^The main industrial application of nanoparticles is in **catalysis **^^due to their high surface area to volume ratios
    • Titanium dioxide in nanoparticle form is ^^used in sunscreens as it blocks UV light^^ but leaves no white marks on the skin while also providing better coverage than otherĀ sun creams
    • ^^Fullerenes^^ ^^are used in medicine and drug design^^ as they are more easily absorbed than other particles and can deliver drugs to target areas more effectively
    • Fullerenes are also used in ^^electronic circuitry^^ and as coatings for artificial limbs and joints
    • Nanoparticles of silver are sprayed onto the fibres of medical clothing and surgical masks which gives them the flexibility of a material but with the added ^^benefit of the antibacterial properties of silver metal^^

==Risks of Nanoparticles==

  • Nanoparticles have widespread uses and applications that can provide an immense advance in materials technology
  • However, the use of nanoparticles in science is in its early stages so there are still a lot of unknown factors and potential risks
  • In particular there is a lack of understanding on how they may affect health
  • Although there havenā€™t been any serious short term side effects, there could be long term side effects which we havenā€™t detected yet as they havenā€™t been in use long enough
  • Even a small amount of toxicity in a particular nanoparticle would be multiplied due to the high surface area to volume ratio
  • This coupled with the fact that they are not easily disposed of by the body are a cause for caution in the medical application of nanoparticles