Evaporation-driven self-organization of sol-gel dip-coating films

Abstract

In this review, we discuss the spontaneous pattern formation of sol-gel dip coating films induced by solvent evaporation, as a novel patterning technique. Linearly arranged striations and cell-like patterns were obtained upon withdrawing the substrate from the coating solution at increasing withdrawal rates. Such highly ordered micropatterns formed by the Bénard-Marangoni convection mechanism triggered by solvent evaporation. In contrast, dip-coating at rates below 1.0 cm min-1 generated periodic stripe patterns arranged on the surface of the films that were perpendicular to the substrate withdrawal direction. Such a formation design was attributed to the onset of capillary flow of the coating solution at the meniscus induced by solvent evaporation.