Highly ordered microporous polystyrene-b-poly(acrylic acid) films: Study on the influencing factors in their fabrication via a static breath-figure method

A series of well-defined amphiphilic polystyrene-b-poly(acrylic acid) (PS-b-PAA) diblock copolymers with different molar ratios of PS and PAA segment were were synthesized via subsequential atomic radical polymerizations of styrene and tert-butyl acrylate (tBuA) followed by hydrolyzation of tert-butyl groups. Highly ordered microporous films of such copolymers were fabricated by a static breath-figure (BF) method using carbon dioxide (CS2) or chloroform (CHCl3) as solvent under a saturated relative humidity of water. The porous films of PS-b-PAA copolymers with average pore size of 0.64–1.79 μm and good regularity were fabricated. Some critical influencing factors, such as concentration of the diblock polymer solution, solvent, temperature, particularly molar ratio of PAA and PS segment were investigated to control the morphology of PS-b-PAA microporous films.