Dresden 2014 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 11: Interfaces and Thin Films I
CPP 11.1: Vortrag
Montag, 31. März 2014, 16:30–16:45, ZEU 114
Guiding Reorganization in Block Copolymer Thin Films on the Nanoscale by Judicious Control of Solvent Vapor Exposure — Alessandro Sepe1, Dorthe Posselt2, Jianqi Zhang1, Jan Perlich3, Detlef-M. Smilgies4, Andrey A. Rudov5, Igor I. Potemkin5, and •Christine M. Papadakis1 — 1TU München, Garching — 2Roskilde University, Denmark — 3DESY, Hamburg — 4Cornell University, Ithaca, NY, USA — 5Lomonosov Moscow State University, Russian Federation
A perfect alignment of nanostructured block copolymer thin films is mandatory for their applications. Solvent vapor annealing is a method to improve order in films prepared by spin-coating. We investigate thin films of lamellar poly(styrene-b-butadiene) (P(S-b-B)) in cyclohexane vapor. The rates of swelling in solvent vapor and drying as well as the maximum degree of swelling of the film are controlled. The structural changes are monitored in-situ using time-resolved grazing-incidence small-angle X-ray scattering (GISAXS). Good alignment of the lamellar nanostructure is achieved for a sufficiently high degree of swelling and is even further improved during drying, provided the rate of drying is sufficiently low. A second swelling/drying cycle shows that equilibrium has been achieved. During swelling, the lamellar stack rearranges as soon as Tg of PS is crossed, and additional lamellae are formed. During (slow) drying, this new structure is conserved. Computer simulations confirm this mechanism [2].
1. A. Sepe et al., submitted.
2. A.A. Rudov et al., Macromolecules 46, 5786 (2013)