A Single Crystal 2D Hexagonal Array in a Centimeter Scale with a Self-Directed Assembly of Diblock Copolymer Spheres

) has been only realized with expensive lithographic fabrication involving a complicated multichemical process. In this work, we report the production of a highly aligned single-grain 2D crystalline nanoarray over a centimeter-scale large area with a concept of self-directed assembly (SDA) in block copolymer (BCP) thin films. No lithographic guiding pattern is employed in SDA. A sphere-forming BCP is first transformed to transient-cylinders and aligned with shear. The aligned cylinders act as a guiding pattern to restore the sphere-morphology producing a single-grain 2D crystalline array with the following solvent vapor annealing. The SDA process has two governing parameters: orientational order of guiding patterns in the first step and the lattice matching between the transient guiding cylinders and the restored spheres. The successful application of SDA yields a single-grain of 2D crys…