Evaporative assembly of ordered microporous films and their hierarchical structures from amphiphilic random copolymers

Abstract

Ordered microporous films were obtained via evaporative assembly from amphiphilic random copolymers of poly(acryloyl chloride) with self-crosslinked components. The quality and morphology of the porous structures were found to be highly dependent on the ratio of good solvent for the polymer (e.g. acetone) and nonsolvent (e.g. toluene), choice of nonsolvent, and surface chemistry of the supporting substrate. When increasing the polymer concentration in acetone–toluene solution, a morphological evolution from vesicles to microporous films with decreased pore size was observed. Using SU-8 micropillar arrays with spatially controlled surface chemistry to direct the evaporative assembly, we constructed hierarchical microporous structures with tunable pore size and symmetry (e.g. square arrays vs. hexagonal arrays). Finally, we selectively assembled TOPO-stabilized CdSe nanocrystals into the hydrophobic core of the random copolymers dispersed in acetone–toluene, and created fluorescent microporous structures after solvent evaporation.