Gels

A gel is a type of colloid where the dispersed phase is a liquid, and the continuous phase is a solid. Normally, the solid starts as a powder and, when the gel is formed after the addition of the liquid, it becomes a tridimensional network (Figure 1).

Figure 1. Molecular structure of a gel. The continuous phase normally forms a cross-linked network. The spaces in the network are filled with the dispersed phase.

The dispersed phase of a gel can be water or organic solvents, leading to the formation of hydrogels or organogels, respectively.

Gels have a lot of applications in science and they can also be found in daily life, such as foods like table jellies or food ingredients, such as gelatin or agar.