Gels:
A gel is a colloidal system in which a liquid is dispersed in a solid. Under certain conditions, the lyophilic sols may be coagulated to give a semi solid jelly like mass which encloses all the liquid present in the sol. The process of gel formation is called gelation and the colloidal system is called gel. For examples, gum Arabic, gelatin, processed cheese, ferric hydroxide, etc.
Gel may be classified into two types:
- Elastic gels
- Non-elastic gels
Elastic gels:
Elastic gels possess the property of elasticity. They readily change their shape on applying force and return to original shape when the applied force is removed. e.g. gelatin, agar-agar, starch, etc.
Non-elastic gels:
These are the gels which are rigid and do not have the property of elasticity. e.g. silica gel.
