To mix or not to mix that's the question

Colloid chemistry in a nutshell is "To mix what doesn't mix". It concerns mainly the
study of mixtures of chemically different materials that unmix spontaneously
(e.g. water and oil).
The range of colloidal systems and materials of practical
importance is vast. Examples are : aerosols, cement, various composites, dyestuffs,
emulsions, foams, foodstuffs, herbicides, ink, paint, paper, pesticides, pharmaceutical
and cosmetic preparations, photographic emulsions, plastics, rubber, soil, etc.
The quality and the applicability of these materials is mainly determined by
colloidal physical factors such as size, shape and interactions of the dispersed
particles (or macromolecules). These factors are studied with experimental physical-chemical
methods.