Emulsion is a mixture of particles of a liquid (dispersed phase) with the other liquid (dispersing phase). Emulsion composed of three main components: the dispersed phase, dispersing phase, and emulsifier.
There are two types of emulsion, namely:
- Emulsion A / M is water droplets dispersed in oil
- Emulsions M / A is the oil droplets dispersed in water.
Emulsifiers agent (emulsifier)
Emulsion is an unstable system. For that we need a substance called emulsifier stabilizer. Without the emulsifier, the emulsion will be broken and separated into the dispersed phase and medium pendispersinya, light floating above the weight. The addition of an emulsifier to stabilize the emulsion as emulsifier lowers the surface tension gradually. A decrease in surface tension will gradually lower the free energy required for the formation of emulsions become increasingly minimal. This means that the emulsion will be stable if the addition of emulsifier whose function is to lower the free energy of formation of an emulsion as possible. The lower the free energy of formation of the emulsion is an emulsion will be more easily formed. The surface tension decreases due to the adsorption of the emulsifier on the surface of the liquid with the tip of the polar ends in the water and hydrocarbons in the oil.
Labor power caused by the shape of the molecule emulsifier that can be bound either in oil or in water. If the emulsifier is more tied to the water or dissolve in polar substances will be more apt to occur in water-oil emulsions (M / A), and vice versa when the emulsifier is more soluble in non-polar substances, like oil, there will be water in oil emulsion (A / M). Emulsifier wrap grains dispersed liquid with a thin layer, so that these items can not be joined to form the phase kontiniyu. Part of the non-polar molecules soluble emulsifier in the outer layers of grains of fat while the part facing the polar solvent water. In some processes, the emulsion must be solved. However, there is a process in which the emulsion must be maintained to avoid breaking the emulsion.
Emulsifier is also known as protective colloids, which can prevent the process of breaking the emulsion, for example: Gelatin, used in the manufacture of ice cream; soaps and detergents; Protein; Paint and ink; Electrolytes. The stability of pure solutions Emulsions When the two are not mutually mix / dissolve like oil and water, mixed, then shaken vigorously, then they will form a dispersion system called emulsion. Physically it looks as though one is next phase in the other phase. When the process is stopped pengocokkan, then very quickly back to separation will occur, so the actual condition of the emulsion appears and is observed in the dispersion system occurs within a very short time. The stability of emulsions is determined by two forces, namely:
- Force of attraction known as the style of the London-van der Waals forces. This style causes the colloidal particles assemble to form aggregates and precipitate,
- Style repulsion caused by squeezing pertumpang-charged electric double layer of the same. This style will stabilize colloidal dispersions.
Factors that affect the stability of the emulsion, are:
- Low interfacial tension
- Mechanical strength and elasticity of the interface layer
- Electric double layer Tolakkan
- Relativity small dispersing phase
- High viscosity.