I would like to point out a great talk given by my friend Mikki Larner over at Plasma Blog which gives an easy-to-understand rundown of the basics of plasma treatment of surfaces. For those new to this whole thing, not all hydrophilic coatings will stick to all surfaces. In order to get a hydrophilic coating to adhere to a surface, some materials require that you treat them with energized plasma (i.e. the fourth state of matter), which functionalizes or at least charges the surface to provide the chemistry necessary to make the coating stick.
The paragraph above is greatly simplified, but this video describes the process in more detail.
Often, some sort of test will follow the coating process, such as pinch testing.