Breath-Figures Formation: Physical Aspects

Abstract

Physical aspects of the process of the breath-figures self-assembly are surveyed. The main physical processes involved in the process are: (1) evaporation of the polymer solution; (2) nucleation of water droplets; (3) condensation of water droplets; (4) growth of droplets; (5) evaporation of water; and (6) solidification of polymer giving rise to the eventual microporous pattern. Hierarchy of the temporal and spatial scales inherent for the breath-figures self-assembly is elucidated. Dimensionless numbers describing the process are supplied. Topological aspects of the self-assembly are considered. Crucial role of the solvent, including its interfacial properties, in the process is addressed in detail. Role of the interfacial Marangoni flows in the formation of the large-scale pattern is treated. The physical properties of the substrate influence the eventual pattern. Nucleation, condensation, and growth of water droplets are addressed in detail. Physical mechanisms of micro-scaled ordering in the breath-figures self-assembly are discussed. The role of the capillary attraction is clarified.