DEWETTING BETWEEN A POROUS SOLID AND A RU BBER

A thin sheet of water E(thickness e) is confined between a rubber C an d a porous substrate P. A dry spot is assumed to nucleate and then gro ws-if the interfacial energies favor dewetting. Around the dry patch, we then expect a water rim, of thickness e + h. The water is ultimatel y sucked in (by capillary forces) inside the pores of P. For this situ ation, we estimate (via simple scaling laws), the growth velocity V of the dry patch. This discussion may possibly be relevant for certain m isfunctions (''print mottle'') observed in 4-colour offset printing, w hen a printing plate C faces a wet paper. However, the role of the ink , and the possibility of an ink/water emulsion are not incorporated he re.