Internal Structure of Ultrathin Diblock Copolymer Brushes
| Autor: | Mark D. Foster, Xuefa Li, Bulent Akgun, Jin Wang, William J. Brittain, Qiang Wang, Gökçe Uǧur, David T. Wu, Huimin Li, Charles F. Majkrzak |
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| Rok vydání: | 2009 |
| Předmět: |
Materials science
Polymers and Plastics Small-angle X-ray scattering Atom-transfer radical-polymerization Organic Chemistry Analytical chemistry Polymer brush Inorganic Chemistry chemistry.chemical_compound chemistry Polymer chemistry Materials Chemistry Copolymer Grazing-incidence small-angle scattering Lamellar structure Polystyrene Methyl acrylate |
| Zdroj: | Macromolecules. 42:8411-8422 |
| ISSN: | 1520-5835 0024-9297 |
| Popis: | The internal structure of as-deposited, high grafting density, ultrathin (thickness < 25 nm) diblock copolymer brushes (DCBs) is resolved using neutron reflectivity (NR) and grazing incidence small-angle X-ray scattering (GISAXS). DCBs of various thicknesses containing deuterated polystyrene (dPS) blocks and poly(methyl acrylate) (PMA) blocks with dPS (dPS-b-PMA) or with PMA (PMA-b-dPS) adjacent to the substrate were synthesized by atom transfer radical polymerization (ATRP). For the thinnest films, a model of two layers with a smooth interfacial gradient provides a good description of the data. For thicker dPS-b-PMA samples of sufficiently asymmetric composition, a third layer must be included. This is consistent with the presence of lateral ordering in the center of the brush, as evidenced by GISAXS data. For the thinnest DCBs, the gradient in composition perpendicular to the surface extends through nearly the entire thickness of the brush, consistent with the conjecture that the gradient is imposed by ... |
| Databáze: | OpenAIRE |
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