Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 37: Poster Session 2

CPP 37.27: Poster

Mittwoch, 2. April 2014, 15:00–19:00, P3

Influence of monomeric structure on the slip boundary condition of polymeric liquids — •Mischa Klos, Sebastian Backes, Matthias Lessel, and Karin Jacobs — Saarland University, Experimental Physics, D-66041 Saarbrücken

With further miniaturization of microfluidic devices the role of the solid/liquid interface gets more important for the flow dynamics. Our experiments probe slippage using the dewetting process of thin polymer films on hydrophobic substrates [1]. As hydrophobic coatings we use amorphous polymers (AF1600, AF2400) and different types of highly ordered self-assembled silane monolayers on top of silicon substrates. On silane surfaces, polystyrene (PS) of low molecular weight shows slip lengths up to micrometers [2]. On AF1600, no significant slip is observable. Recent studies using scattering techniques reveal an ordering of the PS side chains at the solid/liquid interface depending on the structure of the substrate [3]. The situation changes if PMMA or PVP are used: The side groups of PS feature a homogeneous electron environment, yet those of PVP are disturbed by a nitrogen atom, PMMA has no side rings at all. The dewetting experiments show that the slip effect is less pronounced in systems with PVP or PMMA. X-ray scattering methods supplement those findings and give further insight to the slippage mechanism at the solid/liquid interface.[1]O. Bäumchen, et.al., J Phys Condens Matter 24 (2012) 325102 [2]R. Fetzer, et. al, Europhys Lett 75 (2006) 638 [3]P. Gutfreund, et. al.,Phys Rev E 87 (2013) 012306