Kinetic control of preparing honeycomb patterned porous film by the method of breath figure

In this article, linear and star-shaped poly(styrene-block-butadiene) copolymers have been used to study the kinetics of breath figure fabrication, which is a well known method to prepare honeycomb patterned porous film. The fabrication was carried out in an almost sealed chamber, in which a relatively stable water vapor was obtained by positioning some water in advance. The influences of the solvent evaporation speed and the water vapor pressure on the breath figure fabrication were studied. The effect of the starting polymer concentration on the formation of honeycomb porous pattern were investigated in detail. The results indicate that the polymer solution could reach a level of “solidification” to fix the condensed water droplets in a reasonable time of solvent evaporation, and to prevent the water droplets from coalescing. Therefore, a proper solvent vapor together with a fair fabrication temperature are required in order to obtain a honeycomb patterned porous film with good quality. The thus obtained honeycomb film was further UV irradiated for cross-linking to improve its properties such as solvent and thermal resistances, so that broadened applications of such films could be expected.