Silicones (R2SiO)n

Properties: Insulating (electrically and thermally), inert (chemically and biochemically), water repellent, non-inflammable, thermally stable, low surface tension, nontoxic

 

Sounds good. How do you make them?

Start with SiCl4 and treat it with RMgx,

Then what do you do?

Treating R2SiCl2 with water gives you a chain forming group,

Treating R3SiCl with water gives you a chain terminating group,

The length of chain (proportional to n) depends on the ratio of the amounts of these two molecules in the reaction mixture.

RSiCl3 when treated with water forms cross links in the polymer.