Berlin 2005 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 5: SYMPOSIUM: Dynamics of multi-component fluids POSTER

CPP 5.21: Poster

Friday, March 4, 2005, 17:15–19:00, Poster TU D

Running droplets through chemical decomposition of block copolymers in thin films — •Stephan Weiß, Andriana Horvat, Armin Knoll, Larissa Tsarkova, and Robert Magerle — Physikalische Chemie II, Universität Bayreuth, 95440 Bayreuth

We investigate 30-100 nm thin films of poly(styrene)-block-poly(ethylenepropylene) (PS-PEP). Upon annealing in air (in the range of 130-190 ^∘C) the microdomain structure coarsens and forms ∼ 0.3 µm large PS domains embedded in a PEP matrix. When two PS domains coalesce, the resulting domain starts to move spontaneously across the surface and grows to a macroscopic droplet. Behind the droplet a ∼10 nm thick film is left. The phenomenon is followed with tapping mode scanning force microscopy and optical microscopy. We show that a chemical reaction with oxygen is essential for droplet motion. We study the influence of film thickness, annealing temperature, and atmosphere on the kinetics of the phenomenon. Similarities and differences to other reactive wetting phenomena are discussed.