Plasma treatment is able to increase the wettability of most polymers. Hydrophobic recovery is often encountered which causes wettability to decrease.
Powder wettability can be measured with Washburn method or sessile drop.
Capillary action, also called capillary filling or wicking, means the spontaneous flow of liquid to fill small capillaries or pores.
Plasma treatment is an often-used process prior to coating, printing or gluing to improve the wettability of the material.
Contact lens should support a continuous tear film for optimum visual clarity. It should also resist the sorption of tear components as deposition can lead to decreased visual clarity and discomfort. Wettability of the surface affects both the tear film as well as biocompatibility of the lens.
Wettability is the preference of a liquid to be in contact with a solid surrounded by another fluid (liquid or gas). Depending on the application, wettability can be wanted or not.
In industry, wettability is important for example when manufacturing electronics or when planning how to extract oil from the oil reservoir. In all these applications, knowing the contact angle value gives a strong indication on the performance of the product or a successfulness of the process.
Contact angle is easy to understand visually. It is the angle a droplet forms in contact with a solid surface. Thermodynamically, it is a balance between different forces acting on a three-phase contact point where solid, liquid and air meet.
With increasing understanding of the superhydrophobicity, the measurement methods to quantify the degree of hydrophobicity deserve some thought.