Dresden 2006 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 20: SYMPOSIUM Microfluidics I: Boundary conditions, manipulation, and transport

CPP 20.2: Talk

Thursday, March 30, 2006, 10:00–10:15, ZEU 160

Polymer melts slip over solid surfaces: Experimental studies of the slip length — •Renate Fetzer¹, Markus Rauscher², and Karin Jacobs¹ — ¹Dept. of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany — ²MPI for Metal Research, D-70569 Stuttgart, Germany

We present a novel method to asses the slip length and viscosity of thin films of highly viscous Newtonian liquids. We quantitatively analyze dewetting fronts of low molecular weight polystyrene melts on Octadecyl- (OTS) and Dodecyltrichlorosilane (DTS) polymer brushes. Using a thin film (lubrication) model derived in the limit of large slip lengths, we can extract slip length and viscosity of films with thicknesses between 50 nm and 230 nm and temperatures above the glass transition. We find slip lengths from 100 nm up to 1 micron on OTS and between 300 nm and 10 microns on DTS covered silicon wafers. The slip length decreases with temperature. The obtained values for the viscosity are consistent with independent measurements.