1nm =
10-9 m
Size of nanoparticles
1-100nm in size
Bulk material
Not a nanoparticle
The smaller a particle
the larger the surface area to volume ratio
As a cube decreases in size by a factor of 10
Its surface area:volume ratio increases by a factor of 10
Nanoparticles have different properties to bulk materials because
Most atoms are at the surface and they have a high surface area to volume ratio
Uses of nanoparticles
Catalysts, in electronics, in sunscreens.
Advantages of nanoparticles in sunscreen
Better coverage, more effective protection from UV
Disadvantages of nanoparticles in sunscreen
Small enough to enter the bloodstream, could damage cells, could damage the environment
Number of atoms in a nanoparticle
A few hundred atoms
Risks of nanoparticles are unknown
They have not been used for very long
Properties of nanoparticles
Very different to bulk material