Bulk & Surface Properties of Matter Including Nanoparticles

9.35C Compare the size of nanoparticles with the sizes of atoms and molecules
  • Nanoparticles are 1-100 nanometers across.
  • They contain a few hundred atoms.
  • Nanoparticles, are smaller than fine particles (PM2.5), which have diameters between 100 and 2500 nm (1 x 10^-7 m and 2.5 x 10^-6 m).
    • Coarse particles (PM10) have diameters between 1 x 10^-5 m and 2.5 x 10^-6 m.
    • Coarse particles are often referred to as dust.
  • As the side of cube decreases by a factor of 10 the surface area to volume ration increases by a factor of 10
9.36C Describe how the properties of nanoparticulate materials are related to their uses including surface area to volume ratio of the particles they contain, including sunscreens
  • Nanoparticles involve fullerenes.
  • A nanoparticle has different properties to the ‘bulk’ chemical it’s made from, because of their high surface area to volume ratio. It may also mean that smaller quantities are needed to be effective than for materials with normal particle sizes. e.g fullerenes have different properties to big lumps of carbon.
  • They have a high surface area to volume ratio, and therefore would make good catalysts.
  • They can also be used to produce highly selective sensors.
  • Nanotubes could make stronger, lighter building materials.
  • New cosmetics, e.g sun tan cream and deodorant. They make no white marks.
  • Lubricant coatings, as they reduce friction. These can be used for artificial joints and gears.
  • Nanotubes conduct electricity, so can be used in small electrical circuits for computers. 
9.37C Explain the possible risks associated with some nanoparticulate materials
  • Some worries that they may be harmful to health – i.e. enter bloodstream and cause harm
  • A lot of effects of nanoparticulate materials are unknown and this is worrying for some people as risks are not fully known
9.38C Compare, using data, the physical properties of glass and clay ceramics, polymers, composites and metals
  • Most of the glass we use is soda-lime glass, made by heating a mixture of sand, sodium carbonate and limestone
    • Borosilicate glass, made from sand and boron triocide, melts at higher temperatures than soda-lime glass
  • Clay ceramics, including pottery and bricks, are made by shaping wet clay and then heating in a furnace
  • Properties of polymers depend on what monomers they are made from and the conditions under which they are made.
    • Low density polyethene and high density polyethene, are both made under different reaction conditions using different catalysts.
      • Low density polyethene has weaker forces of attraction as the chains are further apart.
        • LD polyethene also has a low melting point and is soft.
      • HD polyethene has higher forces of attraction, as the chains are closer together.
        • HD polyethene has a high melting point.
      • Thermosoftening polymers are made of individual, tangled polymer chains which are easily separated.
      • There are weak intermolecular forces between the chains
      • The chains are easy to separate
      • At lower temperatures
      • Less heat energy is needed to break the chains
      • Thermosetting polymers consist of polymer chains, which cross links, so that they do not melt when heated.
      • Most composites are made of two materials, a matrix or binder surrounding and binding together fibres or fragments of the other material, which is called the reinforcement
9.39C Explain why the properties of a material make it suitable for a given use and use data to select materials appropriate for specific uses

*see 9.38C