Although
a broad definition, we categorise nanomaterials as those which have
structured components with at least one dimension less than 100nm. Materials
that have one dimension in the nanoscale
(and are extended in the other two dimensions) are layers, such as a thin films or surface coatings. Some of the features on
computer chips come in this category. Materials that are nanoscale in two dimensions (and extended in one
dimension) include nanowires
and nanotubes.
Materials that are nanoscale
in three dimensions are particles, for example precipitates, colloids and quantum
dots (tiny particles of semiconductor materials). Nanocrystalline materials, made
up of nanometre-sized
grains, also fall into this category. Some of these materials have been
available for some time; others are genuinely new. The aim of this chapter is
to give an overview of the properties, and the significant foreseeable applications of some key nanomaterials.
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