In-situ reflectometry observation on structural changes of thin self-assembled block copolymer films

N. Torikai, N. L. Yamada, D. Kawaguchi, A. Takano, Y. Matsushita, E. Watkins, J. P. Majewski, H. Okuda

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Abstract

The structural changes induced by solvent contact or heating were observed for thin spin-coated polystyrene-block-poly(2-vinylpyridine) diblock copolymer (PS-P2VP) films using in-situ neutron reflectivity and grazing-incidence small-angle X-ray scattering (GISAXS) techniques. The lamellarly-ordered PS-P2VP film showed some structural changes in contact with water though it is a poor solvent for both the component polymers, while the original structure was recovered after drying the film. When toluene was used as a selectively good solvent for PS, the thin film was dissolved into the solvent. On the other hand, the thin as-prepared PS-P2VP film with spherical microdomains exhibited laterally a pair of scattering spots symmetrical relative to the specular reflection ridge in the GISAXS pattern, indicating the existence of some lateral structural correlation in the film. On a temperature jump up to 200 °C, these two scattering spots started to disappear around the glass transition temperature, and then almost completely vanished at 200 °C unexpectedly though the PS-P2VP used here should be kept in the strong-segregation state. The spherical structure could be completely disordered or kept ordered but with lateral distortion in its orientation. Being cooled down to a room temperature again, the two scattering spots were recovered, and became more intense with their position shifting slightly to lower QY-region than before heating due to the improvement in ordering.

Original languageEnglish
Article number012028
JournalJournal of Physics: Conference Series
Volume83
Issue number1
DOIs
Publication statusPublished - Jun 1 2007
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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