Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 61: Interfaces and Thin Films I (joint session CPP/DY, organized by CPP)
CPP 61.5: Vortrag
Donnerstag, 10. März 2016, 17:30–17:45, H51
Structure of films prepared from block copolymer mixtures: computer simulations and GISAXS experiments — •Anatoly V. Berezkin1, Justus Oberhausen1, Florian Jung1, Dorthe Posselt2, and Christine M. Papadakis1 — 1Technische Universität München, Physik Department — 2Roskilde University, Department of Science, Systems and Models, Denmark
Block copolymer films are promising as nano-structured templates, e.g. for lithography. Mixtures of block copolymers provide a robust route towards the preparation of non-trivial morphologies with an easily controlled domain size. We investigated a mixture of short and long symmetric diblock copolymers experimentally using GISAXS and in simulations (dissipative particle dynamics). We addressed the case, when macrophase separation of the mixture is expected along with the microphase separation in each of two phases. Simulations, in accordance with the experiment, show that the phase rich in short chains is usually located near the film surfaces, while long chains concentrate in the film core. Thick lamellae in the film core are usually perpendicular to the substrate, while thin lamellae in the interfacial layers can be parallel or perpendicular, depending on polymer/surface interactions. Selective adsorption of one block stabilizes lying lamellae. In very thin films confined between two selective surfaces, the conflict between orientations of thick standing lamellae and thin lying lamellae leads to unusual lens-like non-orthogonal structures.