ORGS3-0119
Large-Area Single-Grain Hexagonally Perforated Lamella of Block Copolymers via Composition-Programmed Directed Self-Assembly
When and Where
Nov 30, -0001
12:00am - 12:00am
Presenter(s)
Sang Hyun Choi (Seoul National University)
Co-Author(s)
Abstract
Self-assembly of block copolymers (BCPs) in thin films has attracted great attention as a platform for bottom-up nanopatterning. For industrial implementation of BCP nanopatterning, it is essential to fabricate single-grain structures over centimeter-scale areas. Single-grain cylinders, spheres, and lamellae have been realized using top-down guiding patterns or external fields. However, to the best of our knowledge, the fabrication of single-grain hexagonally perforated lamella (HPL) has not been reported.
We demonstrate, for the first time, centimeter‑scale single‑grain HPL in block copolymer thin films via composition‑programmed directed self‑assembly. We use polystyrene‑b‑poly(2‑vinylpyridine) (PS‑b‑P2VP) thin films, in which aligned cylinders serve as an internal guiding template, to achieve single‑grain HPL formation without top‑down lithography. HPL-forming PS-b-P2VP BCPs were blended with short PS homopolymers to reduce the effective P2VP volume fraction to the cylinder-forming composition regime. The resulting cylinders are shear-aligned over centimeter-scale areas. To recover the native HPL-forming composition while leaving the aligned cylinders intact, the short homopolymers were selectively removed by non-solvent immersion. Subsequent thermal annealing induces a cylinder-to-HPL transition in which the aligned cylinders act as a guiding pattern, yielding HPL with a uniform in-plane orientation over a 1 cm2 area. The single-grain nature was confirmed by grazing-incidence small-angle X-ray scattering (GISAXS) and scanning electron microscopy (SEM). This approach offers a facile and programmable platform to fabricate single-grain HPL nanopatterns for nanolithography, plasmonic devices, and functional nanomaterial templates.
We demonstrate, for the first time, centimeter‑scale single‑grain HPL in block copolymer thin films via composition‑programmed directed self‑assembly. We use polystyrene‑b‑poly(2‑vinylpyridine) (PS‑b‑P2VP) thin films, in which aligned cylinders serve as an internal guiding template, to achieve single‑grain HPL formation without top‑down lithography. HPL-forming PS-b-P2VP BCPs were blended with short PS homopolymers to reduce the effective P2VP volume fraction to the cylinder-forming composition regime. The resulting cylinders are shear-aligned over centimeter-scale areas. To recover the native HPL-forming composition while leaving the aligned cylinders intact, the short homopolymers were selectively removed by non-solvent immersion. Subsequent thermal annealing induces a cylinder-to-HPL transition in which the aligned cylinders act as a guiding pattern, yielding HPL with a uniform in-plane orientation over a 1 cm2 area. The single-grain nature was confirmed by grazing-incidence small-angle X-ray scattering (GISAXS) and scanning electron microscopy (SEM). This approach offers a facile and programmable platform to fabricate single-grain HPL nanopatterns for nanolithography, plasmonic devices, and functional nanomaterial templates.
