Macroporous Polymer Thin Film Prepared from Temporarily Stabilized Water-in-Oil Emulsion

We report a simple and convenient method for fabricating ordered porous structure in a polymeric thin film. A temporarily stabilized water-in-oil emulsion, where aqueous droplets were dispersed in the medium of polymer−organic solvent solution, was utilized for the preparation of porous structure. The water-in-oil emulsion was simply prepared by sonicating the mixture of water and polymer−organic solvent solution without any colloid stabilizer. The growth of aqueous droplets was profoundly retarded by dissolving a small amount of sucrose, selectively soluble in the dispersed phase. The prepared emulsion was recovered onto a substrate through dip-coating and subsequently air-dried to get a well-ordered porous polymer film. The polymer content in the polymer solution phase and the compositional ratio of the aqueous phase to the polymer solution phase was optimized to fabricate well-ordered structures.