Wetting transitions

When a liquid droplet is put onto a surface, two situations distinguishable by the contact angle may result. If the contact angle is zero, the droplet spreads across the surface, a situation referred to as complete wetting. Second, if the contact angle is between 0° and 180°, the droplet does not spread; a situation called partial wetting. A wetting transition is a surface phase transition from partial to complete wetting. We present experiments that show three different ways in which the wetting transition can come about.