Understanding Fluid Gel Formation And Properties

Understanding Fluid Gel Formation And Properties

Write a short note on gel structure.
Answer:

A gel is a semisolid and is produced from a sol during the process of gelation by the formation of the first or chains or micelles of the dispersed phase which become interlocked to the given characteristic jelly-like consistency. Within the gel, the first branch and intermesh to form a “brush heap structure”. The dispersion medium is held in the interstices between the fibrils by capillary attraction or adhesion.

Gelation may be brought about in one of two ways:

• Lowering the temperature, for example, Agar
• By a chemical reaction, for example, Alginate

Gel strength depends on:

• The density of the fibrillar structure—Greater the concentration, greater will be the number of micelles and hence the greater the brush heap density.
• Filler particles become trapped in the fibrillar network and their size, shape, and density determine their effectiveness. Addition of filers also increases the viscosity of sol.