DNA brings materials to life

DNA-coated colloids have been used to create novel self-assembling materials in a breakthrough experiment by EPFL and University of Cambridge scientists.

What do phasons look like?

(Phys.org) -- When illuminated by laser light, assorted colloidal particles can arrange themselves into highly ordered structures called quasicrystals. By changing the phases of the lasers, researchers can force the colloids ...

Researchers develop method to create colloidal diamonds

The colloidal diamond has been a dream of researchers since the 1990s. These structures—stable, self-assembled formations of miniscule materials—have the potential to make light waves as useful as electrons in computing, ...

A water splitter with a double role

(PhysOrg.com) -- There is a lot of hope invested in hydrogen, but it also presents some problems. It is energy-rich, clean and, as a constituent of water, of almost unlimited availability. However, so far it has been difficult ...

Defying gravity with the Brazil nut effect

Physicists from the University of Utrecht and the Faculty of Physics at the University of Warsaw have observed—for the first time experimentally—the Brazil nut effect in a mixture of charged colloidal particles.

On-demand glass is right around the corner

A research group coordinated by physicists of the University of Trento was able to probe internal stress in colloidal glasses, a crucial step to controlling the mechanical properties of glasses. Their work opens the way to ...

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Colloid

A colloid is a substance microscopically dispersed evenly throughout another substance.

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. In addition to these naturally occurring colloids, modern chemical process industries utilize high shear mixing technology to create novel colloids.

The dispersed-phase particles have a diameter of between approximately 5 and 200 nanometers. Such particles are normally invisible in 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 affected largely 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 solutions (also called colloidal suspensions) are the subject of interface and colloid science. This field of study was introduced in 1861 by Scottish scientist Thomas Graham.

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