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Abstract Block copolymer brushes are of great interest due to their rich phase behavior and value‐added properties compared to homopolymer brushes. Traditional synthesis involves grafting‐to and grafting‐from methods. In this work, a recently developed “polymer‐single‐crystal‐assisted‐grafting‐to” method is applied for the preparation of block copolymer brushes on flat glass surfaces. Triblock copolymer poly(ethylene oxide)‐b‐poly(l‐lactide)‐b‐poly(3‐(triethoxysilyl)propyl methacrylate) (PEO‐b‐PLLA‐b‐PTESPMA) is synthesized with PLLA as the brush morphology‐directing component and PTESPMA as the anchoring block. PEO‐b‐PLLA block copolymer brushes are obtained by chemical grafting of the triblock copolymer single crystals onto a glass surface. The tethering point and overall brush pattern are determined by the single crystal morphology. The grafting density is calculated to be ≈0.36 nm−2from the atomic force microscopy results and is consistent with the theoretic calculation based on the PLLA crystalline lattice. This work provides a new strategy to synthesize well‐defined block copolymer brushes.
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Preparation of Macroscopic Block‐Copolymer‐Based Gyroidal Mesoscale Single Crystals by Solvent Evaporation
Abstract Properties arising from ordered periodic mesostructures are often obscured by small, randomly oriented domains and grain boundaries. Bulk macroscopic single crystals with mesoscale periodicity are needed to establish fundamental structure–property correlations for materials ordered at this length scale (10–100 nm). A solvent‐evaporation‐induced crystallization method providing access to large (millimeter to centimeter) single‐crystal mesostructures, specifically bicontinuous gyroids, in thick films (>100 µm) derived from block copolymers is reported. After in‐depth crystallographic characterization of single‐crystal block copolymer–preceramic nanocomposite films, the structures are converted into mesoporous ceramic monoliths, with retention of mesoscale crystallinity. When fractured, these monoliths display single‐crystal‐like cleavage along mesoscale facets. The method can prepare macroscopic bulk single crystals with other block copolymer systems, suggesting that the method is broadly applicable to block copolymer materials assembled by solvent evaporation. It is expected that such bulk single crystals will enable fundamental understanding and control of emergent mesostructure‐based properties in block‐copolymer‐directed metal, semiconductor, and superconductor materials.
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- Award ID(s):
- 1719875
- PAR ID:
- 10459540
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 31
- Issue:
- 40
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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