Most of you have experienced the formation of droplets on the water repellent coating of raincoats, or the spreading of surfactant-containing water on various substrates. In a similar vein, you may well have witnessed the dissolving of edible packaging films in boiling water, or the swelling of natural rubber or SBR in oils…
All of these these phenomenons are related to the active characteristics of the considered chemicals and polymers that are, for the previous cases:
* Hydrophobic
* Hydrophilic
* Lipophilic.
Hydrophilic, hydrophobic, amphiphilic…? Not too complicated!…But not very simple!
Some of them are attracted by fatty products. These are: lipophilic or olephilic
Others are attracted by water, they are hydrophilic
However, in addition some chemicals often include several chemical patterns that lead to various situations according to:
* Lipophilic (or olephilic)/hydrophilic ratio:
Polyethylene wax CH3 - (CH2)n - CH3 is lipophilic and hydrophobic
Acetic acid CH3-COOH is hydrophilic
* Location of olephilic and/or hydrophilic patterns: