Nanoparticle
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A nanoparticle or ultrafine particle is a particle of matter 1 to 100 nanometres in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100
TEM (a, b, and c) images of prepared mesoporous silica nanoparticles with mean outer diameter: (a) 20nm, (b) 45nm, and (c) 80nm. SEM (d) image corresponding to (b). The insets are a high magnification of mesoporous silica particle.
Idealized model of a crystalline nanoparticle of platinum, about 2 nm in diameter, showing individual atoms.
Nanostars of vanadium(IV) oxide (VO2) exhibiting a crystal clusters structure resembling that of desert roses
1 kg of particles of 1 mm3 has the same surface area as 1 mg of particles of 1 nm3
The characterization of nanoparticles is a branch of nanometrology that deals with the characterization, or measurement, of the physical and chemical properties of nanoparticles. Nanoparticles measure
Nanoparticles differ in their physical properties such as size, shape, and dispersion, which must be measured to fully describe them.
An ultraviolet–visible spectrophotometer can provide information about concentration, size, and shape.
Nanoparticles with different particle sizes can have different physical properties. For example, gold nanoparticles of different sizes appear as different colors.
Dispersion is the degree to which particles clump together into weakly bound agglomerates (pictured) or strongly bound aggregates.