Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 35: Activated and Glassy Dynamics of Soft Matter (joint session CPP/DY, organized by CPP)

CPP 35.1: Vortrag

Mittwoch, 9. März 2016, 09:30–09:45, H51

On the dynamics of densely grafted polymer chains — •Michael Lang, Marco Werner, Ron Dockhorn, and Torsten Kreer — Leibniz Institut für Polymerforschung Dresden, Hohe Straße 6, 01069 Dresden, Germany.

Large scale Monte Carlo simulations of a dense layer of grafted polymer chains in good solvent conditions are used to explore the dynamics of a "polymer brush". Monomer displacements are analyzed resolving the directions parallel and perpendicular to the grafting plane. Auto-correlation functions of segment and partial chain end-to-end vectors are analyzed as function of time. We demonstrate that the terminal relaxation time τ of entangled chains with a degree of polymerization N in a brush is related to the entanglement degree of polymerization, N_e, via τ∝ N³exp(N/N_e). The confining tube in the brush is similarly stretched as the chain conformations with tube diameters perpendicular and parallel to the grafting plane related by a_⊥≈ a_∥(N_e/g)^1/2, whereby g is the number of monomers per correlation volume of the brush. One specific effect of the confining potential is that the terminal part of the perpendicular component of the monomer position vector auto-correlation function decays simultaneously for all monomers.