Wetting and dewetting of structured and imprinted surfaces is discussed fro
m a theoretical point of view. An appropriate separation of length scales i
s used in order to eliminate irrelevant parameters from the theory. This le
ads to a general description of the wetting phase which can exhibit various
morphologies such as droplets, channels or films. We discuss some general
features of heterogeneous surfaces, extended surface domains, and line tens
ion effects. We emphasize (i) the new concept of morphological wetting tran
sitions, which occur both for small and for large surface domains; and (ii)
the importance of studying the scale-dependence of the wetting morphologie
s as one zooms down into the nanoregime. (C) 2000 Elsevier Science B.V. All
rights reserved.