Colloidal Dispersion l Study Pharma l

Colloidal dispersion:

Colloidal dispersion is the dispersion system in which dispersed phase (particle size ranging 1nanometer - 0.5micrometer) dispersed in a dispersion medium.

Properties:

- Not detected by ordinary microscope (although detection done by ultra-microscope).

- Pass through a filter paper easily.

- Do not pass through a semipermeable membrane.

- Diffuse very slowly.

Example:

Cheese, Butter, Milk, etc.

Types of Colloidal dispersion:

1.  Lyophilic colloids

2.  Lyophobic colloids

3.  Association colloids

Lyophilic colloids:

Lyophilic colloidal system in which colloidal range particles have high affinity to dispersed in a dispersion medium. Lyophilic colloids are obtained easily by simply dissolves colloidal materials into dispersion medium.

Example:

Add Acacia in water, dissolution take place after then solvation occur where the attachment of dispersion medium molecule with dispersed phase molecule (because of dispersed phase molecule have high affinity to dispersion medium) to form a colloidal dispersion or sols.

Most of colloidal particles are organic molecules such as gelatin, acacia, albumin, rubber, polystyrene, etc. in which first three are lyophilic colloid materials which  dispersed in aqueous medium, called as Hydrophilic colloids. And remains two are lyophilic colloids materials which dispersed in non-aqueous medium, called as Lipophilic colloids.

Lyophobic colloids:

Lyophobic colloids system in which colloid particles have less dispersed in the dispersion medium (less interaction with solvent molecules). It is called as Lyophobic colloids.

Colloids particles are inorganic materials such as gold, silver, sulfur, etc..

Formation of lyophobic colloids dispersion system by using two special methods:

1. Dispersion method

2. Condensation method

Dispersion method:

In this method, coarser particles reduced in size make colloidal range particles. 

Condensation method:

In this method, charged sub-colloidal range particles associates with colloidal range particles to enhance its interaction with solvent or dispersion medium.

Association colloids:

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