Study reveals how to break symmetry in colloidal crystals

Nature keeps a few secrets. While plenty of structures with low symmetry are found in nature, scientists have been confined to high-symmetry designs when synthesizing colloidal crystals, a valuable type of nanomaterial used ...

Superselective colloid-surface binding visualized

Rather than one key and one strong lock, biology often uses tens or hundreds of weaker links to bind parts together, such as cell membranes. This allows for selectivity and also reversibility—the binding can also be undone. ...

Confined magnetic colloidal system for controllable fluid transport

Colloidal suspensions of microscopic particles show complex and interesting collective behaviors. In particular, the collective dynamics of colloids is fundamental and ubiquitous for materials assembly, robotic motion, microfluidic ...

What stops flows in glassy materials?

Glasses have a liquid-like disordered structure but solid-like mechanical properties. This leads to one of the central mysteries of glasses: Why don't they flow like liquids? This question is so important that it was selected ...

Scientists age quantum dots in a test tube

Researchers from MIPT and the RAS Institute of Problems of Chemical Physics have proposed a simple and convenient way to obtain arbitrarily sized quantum dots required for physical experiments via chemical aging. The study ...

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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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