20 Examples of Colloids

The colloids they are inhomogeneous mixtures made up of a dispersed phase, which is almost always a solid with very small particles, and a dispersing or continuous phase, which is generally liquid or gaseous. For example: heavy cream, latex paint, jelly.

There may also be colloids in which both phases are in any of the three states of aggregation, except that they are both gaseous phases (if both phases are gases, it will not be a colloid but a dissolution).

The word colloid was introduced by the Scottish chemist Thomas graham in 1861 and is derived from the Greek root kolas (κoλλα), which means "sticky" or "unctuous". This is related to the property of this type of substance of not passing through the usual filters.

When a beam of light passes through a colloid, it scatters and becomes visible. This event is known as Tyndall effect. The presence of this optical effect makes it possible to distinguish a colloid from a solution or solution. Colloid particles have a diameter between 1 nanometer and a micrometer; that of solutions are less than 1 nanometer and those of suspensions are greater than 1 micrometer. Colloids have properties intermediate between solutions and suspensions.

Types of colloids

In case the dispersing phase is water, the colloids can be hydrophilic (attraction of its particles with water) or hydrophobic (repulsion of its particles with water).

If the dispersing phase is liquid, the colloids can be lyophobes or lyophilic. In lyophobes there is little attraction between the dispersed phase and the dispersant phase. On the other hand, in lyophiles there is a lot of attraction between both phases.

The physical state of the colloid is generally defined by the physical state of the dispersing phase, which can be liquid, solid or gaseous. The dispersed phase can also correspond to one of these three types, although in gaseous colloids this is always a liquid or a solid.

Colloids can also be classified into:

Uses of colloids

Colloidal substances are important in the formulation of numerous industrial materials of habitual and massive use such as paints, plastics, insecticides for farming, inks, cements, soaps, lubricants, detergents, adhesives and various food products. The colloids contained in the soil contribute to its retention of water and nutrients.

In medicine, colloids or plasma expanders to expand intravascular volume for longer periods than is achieved through the use of crystalloids.

List of examples of colloids

1. Plasma
2. Organic material
3. Milk cream
4. Milk
5. Latex paints
6. Foam
7. Jelly
8. Fog
9. Smoke
10. Montmorillonite and other silicate clays
11. Bovine cartilage
12. Albumin derivatives
13. Dextrans
14. Hydroethyl starches
15. Woven bone
16. Smog
17. Detergents
18. Silica gel
19. Titanium oxide
20. Ruby