Regensburg 2010 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 14: Poster: Interfaces and Thin Films

CPP 14.15: Poster

Monday, March 22, 2010, 16:30–18:00, Poster C

Structural rearrangements in a lamellar diblock copolymer thin film during treatment with saturated solvent vapor — Zhenyu Di¹, Dorthe Posselt², Detlef-M. Smilgies³, and •Christine M. Papadakis¹ — ¹TU München, Physikdepartment E13, Garching — ²IMFUFA, Roskilde University, Denmark — ³CHESS, Cornell University, USA

The processes during vapor treatment of block copolymer thin films, which is often used for equilibrating film structures, are complex. Solvent not only swells the polymers, but also increases the chain mobility and reduces the interfacial tension between the blocks [1].

We have investigated the structural changes in thin films of lamellar poly(styrene-b-butadiene) diblock copolymers during treatment with saturated cyclohexane vapor, a solvent slightly selective for polybutadiene. Using real-time, in-situ grazing-incidence small-angle X-ray scattering (GISAXS) [2], the swelling and the rearrangement of the lamellae were investigated with a time resolution of a few seconds. After a few minutes in vapor, a transient state with a more well-defined and more long-range ordered lamellar orientation was encountered. Additional parallel lamellae formed because of the increased degree of coiling of the polymers in the swollen state. Eventually, the film became disordered.

[1] C. M. Papadakis et al., Langmuir 24, 13815 (2008). [2] D.-M. Smilgies et al, Mater. Res. Soc. Symp. Proc. 1147, OO01-01 (2009) [3] Z. Di, et al., Macromolecules, accepted.