  Evaporation of water droplets deposited on metal and polymer substrates was
studied. The evaporated droplet demonstrates different behaviors on low-pinning
(polymer) and strong-pinning (metallic) surfaces. When deposited on polymer
surfaces, the evaporated droplet is featured by stick-slip sliding, whereas on
strong-pinning metallic surfaces it does not show such kind of motion and
demonstrates the giant contact-angle hysteresis. Stick-slip motion of droplets
is described satisfactorily by the Shanahan-Sefiane model relating this kind of
motion to surmounting potential barriers caused by the pinning of the triple
(three-phase) line. The experimentally established "stick" times coincide with
the values predicted by the Shanahan-Sefiane theory. The values of potential
barriers are reported. The notion of the equilibrium contact angle is refined.
