Directed self-organization of block copolymer micelles on topographic substrates†

The ability to create complex arrays of organized nanostructures is crucial for many advanced technological applications. An extensively investigated methodology for producing such arrays is the directed self-assembly of block copolymers using topographically patterned substrates, where micron-scale features engraved in the substrate induce nanodomain alignment over macroscopic ranges. Most research thus far concentrated on the formation of ordered surface patterns through microphase separation of block copolymers in thin films. In this work, we demonstrate the utility of block copolymer micelles – soft, self-assembled, non-crosslinked entities – for the preparation of arrays with structural bi-modality. Systematic investigation of the influence of the substrate's topography on the micellar assembly at different concentrations revealed different structural behavior of micelles deposited on the plateaus and in the trenches, which is tunable by the topographic feature dimensions. The potential of this approach for effecting complex superstructures is demonstrated by employing the micelles to organize semiconductor nanorods.