6533b823fe1ef96bd127fde8

RESEARCH PRODUCT

Computer Simulation Studies of Chain Dynamics in Polymer Brushes

subject

description

Center-of-mass and single monomer motion in grafted chains comprising a strongly stretched polymer brush in thermal equilibrium are studied by large scale molecular dynamics and Monte Carlo simulations of a coarse-grained model. Good solvent conditions are assumed. Our findings seriously question earlier theoretical predictions about the relaxation described by Rouse dynamics of brush coatings. Thus, the correlation functions of parallel and perpendicular components of the mean distance of the center-of-mass from the grafting site, the squared gyration radius and end-to-end distance, are found to deviate strongly from a simple exponential decay. While the relaxation times extracted from the initial slope of the center-of-mass and the gyration radius correlation functions are roughly compatible with the theoretical prediction τz(i) ∝ N3, τxy(i) ∝ N2, the relaxation times extracted from the late exponential decay scale as τz(f) ∝ τxy(f) ∝ NΔ with an effective exponent Δ ≈ 3.7 for polymers of length 64 ≤ N ≤...