Nanoparticle
A Nanoparticle is a fine particle of matter that is between 1 and 100 nanometres (nm) in diameter.
- Example(s):
- a Virus.
- …
- Counter-Example(s):
- See: Nanotechnology, Matter, Nanometre, Diameter, Colloid, Atom Clusters, Visible Light, Optical Microscope, Electron Microscope, Scattering, Filtration, Chamberland Filter.
References
2020
- (Wikipedia, 2020) ⇒ https://en.wikipedia.org/wiki/nanoparticle Retrieved:2020-3-29.
- A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm,or fibers and tubes that are less than 100 nm in only two directions.
Nanoparticles are usually distinguished from "fine particles", sized between 100 and 2500 nm, and "coarse particles", ranging from 2500 to 10,000 nm. They are a subclass of the colloidal particles, which are usually understood to range from 1 to 1000 nm. Metal particles smaller than 1 nm are usually called atom clusters instead.
Being much smaller than the wavelengths of visible light (400-700 nm), nanoparticles cannot be seen with ordinary optical microscopes, requiring the use of electron microscopes. For the same reason, dispersions of nanoparticles in transparent media can be transparent, , whereas suspensions of larger particles usually scatter some or all visible light incident on them. Nanoparticles also easily pass through common filters, such as common ceramic candles. , so that separation from liquids requires special nanofiltration techniques.
The properties of nanoparticles often differ markedly from those of larger particles of the same substance. Since the typical diameter of an atom is between 0.15 and 0.6 nm, a large fraction of the nanoparticle's material lies within a few atomic diameters from its surface. Therefore, the properties of that surface layer may dominate over those of the bulk material. This effect is particularly strong for nanoparticles dispersed in a medium of different composition, since the interactions between the two materials at their interface also becomes significant.
Nanoparticles occur widely in nature and are objects of study in many sciences such as chemistry, physics, geology and biology. Being at the transition between bulk materials and atomic or molecular structures, they often exhibit phenomena that are not observed at either scale. They are an important component of atmospheric pollution, and key ingredients in many industrialized products such as paints, plastics, metals, ceramics, and magnetic articles. The production of nanoparticles with specific properties is an important branch of nanotechnology.
- A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm,or fibers and tubes that are less than 100 nm in only two directions.