Wetting of Rough Solid Surfaces by Liquids

Recently, newly introduced experimental techniques have advanced our understanding of the phenomena of wetting and spreading of solid surfaces by thin liquid films ranging in thickness between few dozen Angstroms to a fraction of a micron. Among others these include ellipsometry(1)–(3)and grazing incidence X-ray diffraction using a synchrotron source(4)(5). From a theoretical point of view, simple models for profiles of thin liquid films and their relation to the shape of the solid substrate have been proposed for smooth solid surfaces(6), wetting on fibers(7), wetting of porous media and fractals(8). In this short contribution we focus only on the static behavior of thin liquid films that completely wet a rough solid surface(9)–(11). Our predictions can be tested using the experiments mentioned above(1)–(5).