Water Behaviour: Hydrophobic and Hydrophilic Differences
However, there are two main kinds of water behaviour that automotive paint protection provides: Hydrophobic and Hydrophilic. How different are they? To simplify it, hydrophobic allows water to bead into a sphere of water droplets while hydrophilic allow water to sheet off the surface instead of beading into a sphere of water.
Hydrophobic Water Behaviour
Here's an example of how hydrophobic coating reacts to water:
However, there a couple of cons of hydrophobic coatings. If they are not dried properly after a car wash, or rain, it will form hard water spots from the minerals build up on the water droplets and these water spots can be a problem for certain areas that rains often.
Here's a video example of hydrophobic coating water behaviour:
Video courtesy to Project Detail in Sydney.
Hydrophilic Water Behaviour
Here's an example of how hydrophilic coating reacts to water:
Comparing hydrophobic and hydrophilic, hydrophobic promotes more self-cleaning effect and hydrophilic promotes ease of maintenance and drying.
Here's a photo of the differences between the two, 50/50 on a bonnet of a BMW