Although most silicone polymers are not water-soluble, there is one
important class of silicones with water-soluble capabilities – surfactants
(surface acting agents).
Surfactants are used to create emulsions – stable blends of two
“unblendable” materials, like oil and water.
Surfactants have a “split personality.” One part of a surfactant – the
“tail” – is hydrophobic (water-fearing), while the other part – the
“head” – is hydrophilic (water-loving).
Silicone surfactants are organo-modified branched silicone polymers with
many “heads” and many “tails”.
This makes them more efficient than other surfactants, and more
cost effective to use. Silicone polyethers are good examples:
In search of molecular “happiness”
Surfactants are drawn to interfaces – the boundaries between two different
liquids. Interfaces are the only place where both parts of the surfactant
molecule can find “true happiness.”
Because the hydrophilic part of the surfactant is highly soluble in water
and the hydrophobic part is highly soluble in oil, the surfactant engulfs and
stabilizes droplets of one liquid within the other.
The two most common emulsions are water-in-oil and oil-in-water.
Did you know ... silicones love interfaces – all kinds of
interfaces – liquid-liquid, solid-solid, liquid-solid, liquid-gas, solid-gas.
It is where they do some of their best work!