What is the lotus effect?
The lotus effect is a naturally occurring property that is a result of very high water repellency or hydrophobicity, as exhibited by the leaves of the lotus flower. Basically dirt particles are picked up by water droplets due to the micro and nanoscopic architecture of the surface, which minimise the droplets ability to stick to the surface.
What we've created with our Cavalier hydrophobic t-shirt is that same effect applied to a t-shirt. At a microscopic level there are tiny whiskers that repel water droplets.