3-dimensional control over lamella orientation and order in thick block copolymer films

Abstract

The general strategies for achieving macroscopic order in thin block copolymer films typically utilize external stimuli and activation energies, which become less effective with increasing the film thickness to ∼0.5–1 µm. Here we show a facile and effective approach towards multi-level control over lamella orientation and order in thick diblock copolymer films. The novel finding concerns the reorientation of lamella domains relative to the substrate upon annealing under a selective solvent, and is combined with alignment of the lamellar director along a preferred direction by simultaneous application of an electric field. The multiple approach yields a method for the single step fabrication of a striped nanostructure with a controlled orientation and long-range order of the microdomains.