News tagged with colloids
A crowning success for crayfish
Nature sometimes copies its own particularly successful developments. A team of scientists from the Max Planck Institute of Colloids and Interfaces in Potsdam and the Ben-Gurion University at Beer-Sheva in ...
May 21, 2012 |
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Particles magnetically 'click' to form superstructures
(Phys.org) -- Geomag, the popular children's toy, contains small metal spheres that can be magnetically connected with a click to build a variety of towers, bridges, and sculptures. In a new study, scientists ...
Apr 10, 2012 |
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Scientists evaluate different antimicrobial metals for use in water filters
Porous ceramic water filters are often coated with colloidal silver, which prevents the growth of microbes trapped in the micro- and nano-scale pores of the filter. Other metals such as copper and zinc have also been shown ...
Nanotechnology / Bio & Medicine
May 24, 2012 |
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Researchers discover why atoms in solids show a preference for certain structures
(PhysOrg.com) -- Nature likes some symmetries, but dislikes others. Ordered solids often display a so-called 6-fold rotation symmetry. To achieve this kind of symmetry, the atoms in a plane surround themselves ...
Mar 30, 2010 |
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Triblock spheres provide a simple path to complex structures
University of Illinois materials scientists have developed a simple, generalizable technique to fabricate complex structures that assemble themselves.
Jan 19, 2011 |
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Physicists Find a World of Motion In the Mystery of Aging Glass
(PhysOrg.com) -- Physicists super-cooled a liquid into glass in order to observe the slowing of particles. It's a material that still perplexes researchers despite thousands of years of household and industrial use.
Sep 19, 2009 |
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A golden bullet for cancer: Nanoparticles provide a targeted version of photothermal therapy for cancer
In a lecture he delivered in 1906, the German physician Paul Ehrlich coined the term Zuberkugel, or "magic bullet," as shorthand for a highly targeted medical treatment.
Nanotechnology / Bio & Medicine
Mar 12, 2010 |
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Researchers develop new method for the production of microlenses
Inspired from Mother Nature: The body of the brittlestar Ophiocoma wendtii is studded with tiny crystalline lenses made of calcium carbonate. Microlenses like these are of great interest technologically, yet th ...
Mar 26, 2012 |
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Anti-malaria drug synthesized with the help of oxygen and light
The most effective anti-malaria drug can now be produced inexpensively and in large quantities. This means that it will be possible to provide medication for the 225 million malaria patients in developing ...
Jan 17, 2012 |
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Researchers Record First Real-Time Direct Observations of Nanocrystal Growth in Solution (w/ Video)
(PhysOrg.com) -- The veil is being lifted from the once unseen world of molecular activity. Not so long ago only the final products were visible and scientists were forced to gauge the processes behind those ...
Aug 07, 2009 |
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Making complex fluids look simple
An international research team has successfully developed a widely applicable method for discovering the physical foundations of complex fluids for the first time. Researchers at the University of Vienna and ...
Jun 01, 2011 |
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Plant with 'eggbeater' testure inspires waterproof coating
A floating weed that clogs waterways around the world has at least one redeeming feature: It's inspired a high-tech waterproof coating intended for boats and submarines.
Nanotechnology / Nanomaterials
Nov 10, 2011 |
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C60 could form a new kind of gel
(PhysOrg.com) -- C60, the spherical carbon molecule also known as a buckminsterfullerene, has intrigued scientists for its unique properties and potential applications in nanotechnology and electronics. Now scient ...
Nanotechnology / Nanomaterials
Feb 17, 2011 |
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A sweet defense against lethal bacteria
(PhysOrg.com) -- There is now a promising vaccine candidate for combating the pathogen which causes one of the most common and dangerous hospital infections. An international team of scientists from the Max ...
May 31, 2011 |
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Osmosis in colloidal suspensions
(PhysOrg.com) -- It is very difficult to overestimate the importance of colloidal suspensions. Besides being an integral part of our everyday life (food, cosmetics, drugs), they also serve as an excellent ...
May 18, 2011 |
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Colloid
A colloid is a type of chemical mixture where one substance is dispersed evenly throughout another. The particles of the dispersed substance are only suspended in the mixture, unlike a solution, where they are completely dissolved within. This occurs because the particles in a colloid are larger than in a solution - small enough to be dispersed evenly and maintain a homogenous appearance, but large enough to scatter light and not dissolve. Because of this dispersal, some colloids have the appearance of solutions. A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium). A colloidal system may be solid, liquid, or gaseous.
Many familiar substances are colloids, as shown in the chart below. As well as these naturally occurring colloids, modern chemical process industries utilise high shear mixing technology to create novel colloids.
The subsequent table compares particle(s) diameters of colloids, homogeneous and heterogeneous mixture:
Thus, colloid suspensions are intermediate between homogeneous and heterogeneous mixtures. They are sometimes classified as either "homogeneous" or "heterogeneous" based upon their appearance.
The dispersed-phase particles have a diameter of between approximately 5 and 200 nanometers. Such particles are normally invisible to an optical microscope, though their presence can be confirmed with the use of an ultramicroscope or an electron microscope. Homogeneous mixtures with a dispersed phase in this size range may be called colloidal aerosols, colloidal emulsions, colloidal foams, colloidal dispersions, or hydrosols. The dispersed-phase particles or droplets are largely affected by the surface chemistry present in the colloid.
Some colloids are translucent because of the Tyndall effect, which is the scattering of light by particles in the colloid. Other colloids may be opaque or have a slight color.
Colloidal systems (also called colloidal solutions or colloidal suspensions) are the subject of interface and colloid science. This field of study was introduced in 1861 by Scottish scientist Thomas Graham.
For more information about Colloid, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
