Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Polyelectrolytes
CPP 17.8: Vortrag
Dienstag, 8. März 2016, 11:45–12:00, H40
Steady-state shear motion of polyelectrolyte-brush bilayers with oppositely charged polyelectrolyte stars — •Majid Farzin1,2, Torsten Kreer1, and Jens-Uwe Sommer1,2 — 1Leibniz Institute of Polymer Research Dresden Germany — 2Institute of Theoretical Physics, Department of Mathematics and Natural Sciences, Technical University of Dresden Germany
Molecular dynamics simulations are employed to study polyelectrolyte-brush bilayers (PEB) with embedded polyelectrolyte stars (PES) under steady-state shear motion of two grafting surfaces. We use the Ewald-summation method to incorporate electrostatic interactions and the dissipative-particle-dynamics thermostat to account for hydrodynamic correlations. To study the influence of electrostatic interactions, we vary both the Bjerrum length and the fraction of charged brush monomers. Increasing the strength of electrostatic interactions leads to a slightly smaller osmotic pressure concomitant with a larger shear stress. Consequently, the resulting kinetic friction coefficient increases upon increasing of Bjerrum length or charge density. We relate this result to conformational properties, such as the distribution of stars within the bilayer, which depend strongly on the electrostatic interactions. Our study provides a significant advance towards a more realistic modeling of biological transport processes as they have previously preformed for electrically inert brushes of PEB without inclusions.