Well, I used to be a chemist in an earlier part of my career. In addition to the wikipedia link about wetting that was posted above, I recall that in the lab we used substances called "wetting agents" that helped ensure that a liquid covered a surface rather than forming drops on it. Those liquids were not always water of course: they could be a variety of organic solvents, which you may encounter in daily life as things like nail varnish remover.

Here is a link from Chemwiki: http://chemwiki.ucdavis.edu/Physical...Wetting_Agents