Thin film morphologies of block copolymers complexed with wedge-shaped liquid crystalline amphiphilic molecules
Autor(en): | Albrecht, K. Mourran, A. Zhu, X. Markkula, T. Groll, J. Beginn, U. De Jeu, W.H. Moeller, M. |
Stichwörter: | Atomic force microscopy; Complexation; Fourier transform infrared spectroscopy; Liquid crystals; Morphology; Proton transfer; Thin films; X ray photoelectron spectroscopy, Neutralization; Smectic layers; Surface layers; Thin film structure, Block copolymers | Erscheinungsdatum: | 2008 | Journal: | Macromolecules | Volumen: | 41 | Ausgabe: | 5 | Startseite: | 1728 | Seitenende: | 1738 | Zusammenfassung: | Wedge-shaped molecules with a sulfonic group at the tip have been incorporated into a poly(2-vinylpyridine)-b-poly(ethylene oxide) (P2VP-b-PEO) diblock copolymer via proton transfer at different degrees of neutralization. The protonation of P2VP was monitored by means of Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The thin film morphology of the complexed block copolymers has been studied by scanning force microscopy and X-ray reflectivity. The complexes exhibit strongly microphase-segregated patterns comprising smectic layers of the complexed P2VP blocks, oriented parallel to the substrate throughout the whole film with the embedded PEO domains. For the complex with a degree of neutralization of 0.50 ordered amorphous PEO cylinders are observed oriented perpendicular to the substrate. For a degree of neutralization equal to 0.25 initially also perpendicular PEO cylinders are formed, but upon solvent-vapor annealing they partially merge, resulting in a mixed lamellar-cylindrical morphology. In all cases an extra surface layer is formed at the substrate. Thus, for the first time we have demonstrated that a block copolymer thin film structure can easily be controlled by the degree of neutralization of one of the blocks. © 2008 American Chemical Society. |
ISSN: | 00249297 | DOI: | 10.1021/ma071317n | Externe URL: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-41849140869&doi=10.1021%2fma071317n&partnerID=40&md5=3268efa66d9fee7fb70f68dbb5949e4e |
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geprüft am 23.05.2024