Berlin 2005 – scientific programme

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CPP: Chemische Physik und Polymerphysik

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

CPP 5.19: Poster

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

Interface velocity of a structured liquid on solid substrates: a SPM study — •Daniel Podzimek and Karin Jacobs — FR 7.2 Experimental Physics - Soft Matter, Saarland University, D-66123 Saarbrücken

We report novel experiments that enable a direct insight into the flow properties of thin liquid films. The flow properties have been evaluated for liquid fronts that move over solid substrates, driven by interfacial forces arising from the films being deposited onto non-wetting substrates. The dewetting process involves the nucleation and growth of holes induced by heating polymer films above their glass transition temperature. Our experiments are performed on the moving liquid fronts surrounding those holes using a thin block copolymer film as a structured liquid. Since the two blocks of the poly(styrene-ethylene/propylene) copolymer are incompatible, they phase separate and microdomains emerge. Upon shear (induced by dewetting), these microdomains undergo a structural rearrangement and form cylinders. We report first direct SPM experiments on the liquid/solid interface with nanometer resolution. At this interface we find a similar microdomain alignment as on top of the film. This alignment, which is due to a nonzero slippage velocity at the interface, gives us a powerful tool to investigate the slippage length of melts of different viscosities on different substrates.