The sol-gel method involves creating an inorganic network through the formation and gelation of a colloidal suspension. Metal alkoxides and chlorides react with water through hydrolysis and polycondensation reactions to form this network. The sol-gel process is used to create protective coatings, thin films, fibers, and nano-scale powders for opto-mechanical applications and offers advantages over conventional glass production like low temperature operation and better control over material properties at the nano-scale.

1. SOL-GEL
METHOD

2.  involves the evolution of inorganic
networks through the formation of a
colloidal suspension (sol) and gelation of
the sol to form a network in a
continuous liquid phase (gel)

3.  The precursors for synthesizing these colloids
consist :
- metal alkoxides
e.g: tetramethoxysilane (TMOS) and
tetraethoxysilane (TEOS)
-metal chlorides
 they readily react with water.
 three reactions are generally used to
describe the sol-gel process:
- hydrolysis
- polycondensation

4. General equation:
R : -CH3, -C2H5 etc.
M: Si, Al, Ti etc.
Example:

5. Example :

6.  Protective Coatings
 Thin film and fibers
 Nanoscales powder
 Opto-mechanical

7.  Cheap and low temperature operation
 Very thin of metals oxide can be
obtained
 Better alternative approach to
conventional production of glasses
 Sol gel material can be obtained as
bulks, thin films (nano) powders