Dresden 2006 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 9: SYMPOSIUM Disperse Polymer Systems II

CPP 9.8: Vortrag

Dienstag, 28. März 2006, 16:30–16:45, ZEU 160

Structure and dynamics of asymmetric block copolymers in thin films — •Larissa Tsarkova, Andriana Horvat, and Georg Krausch — Physikalische Chemie II, Universität Bayreuth, 95444 Bayreuth

With tapping mode scanning force microscopy (SFM) we study the development of non bulk morphologies in a layer of polystyrene-block-polybutadiene cylindrical domains (C) supported by two chemically different substrates. The mechanism of the thickness induced phase transition shows clear dependence on the substrate induced surface field. On a neutral surface (carbon coating) ordered clusters of the perforated lamella (PL) phase coexist with grains of the C phase. A fraction of the non bulk PL morphology reflects the thickness gradient within a single layer of structures. A strong surface field largely suppresses the mobility of the majority polybutadiene component on the silicon substrate resulting in a C to lamella phase transition. The important contribution of the chains lateral mobility on the structural development is demonstrated by in-situ SFM measurements of the microdomain dynamics. Computer simulations based on dynamic density functional theory (MesoDyn) are in a good agreement with the experimental observations.