In a previous article I focused specifically on the chemistry, properties and applications of hydrophilic polymers. In this article I will look closely into the chemical and physical structure of various other polymers and why this gives them certain performance qualites such as water repellence, lipophilicity, oil repellence.
* The formation of droplets onto the water-repellent coating of raincoats.
* The fogging on inside surface of films wrapping moist products.
* The controlled adhesion of labels on silicone-coated papers.
* The water passing through a fabric made out of a hydrophobic fibre.
All these common facts are related to the combination of several phenomena: surface tension, absorption, and permeability notably.
Clarify some terms
There exists the following possible surface treatments:
* Hydrophobic: chemically repelling water. These polymers generally have a high level of fluorine (fluoropolymers) or other hydrophobic groups (silicone).
* Lipophilic or oleophilic: chemically attracting lipids, fats, grease, oils... They generally are non-polar. Some of them contain some ionic groups and might be considered as amphiphilic.