Main Page | See live article | Alphabetical index

Colloid

A colloid, or colloidal dispersion, is a form of matter intermediate between a true solution and a mixture or suspension. Microscopic particles of one substance, said to be in the dispersed or solute phase, are distributed throughout another, said to be in the dispersing, continuous, or solvent phase.

Colloidal size - 0.001 micron to 1 micron in any dimension. Dispersions where the particle size is in this range are referred to as colloidal aerosols, colloidal emulsions, colloidal foams, or colloidal suspensions.

Colloids can be classified as follows:

  Dispersed Phase
Gas
Liquid
Solid
Dispersing Phase Gas - Liquid aerosol,
e.g.: fog, mist
Solid aerosol,
e.g.: smoke, dust
Liquid Foam,
e.g.: whipped cream
Emulsion,
e.g.: milk, mayonnaise, hand cream
Sol,
e.g.: paint, ink
Solid Solid foam,
e.g.: styrofoam
Gel,
e.g.: gelatin, jelly, cheese
Solid sol,
e.g.: ruby glass