  The contact angle of a fluid droplet on an heterogeneous surface is analysed
using the statistical dynamics of the spreading contact line. The statistical
properties of the final droplet radius and contact angle are obtained through
applications of depinning transitions of contact lines with non-local
elasticity and features of pinning-depinning dynamics. Such properties not only
depend on disorder strength and surface details, but also on the droplet volume
and disorder correlation length. Deviations from Wenzel or Cassie/Baxter
behaviour are particularly apparent in the case of small droplet volumes and
small contact angles.
