Whats the basis of the method?
You can see lots of contact angle phenomena in everyday life. On a clean glass surface, for example, water doesn’t “bead up” in drops. If you take your car through a car wash, though, and order the spray wax option, the glass surface of the car windows becomes coated with an agent that will cause water to form distinct hemispherical drops. Water on a Teflon surface, similarly, makes distinct drops that “curve under” at the edges. Water drops on plastic surfaces can take on a great variety of shapes, depending on the plastic’s composition and its history of chemical or electrical surface treatment. Anti-static electrical treatment of a polyethylene surface, for example, causes water to adsorb on the surface. So before antistatic treatments, water would bead up on the plastic surface, but after treatment the “beads” are essentially flat. That means you could effectively follow the course of anti-static treatment by stopping at different points in mid-treatment, and checking the shape of
