6533b85afe1ef96bd12ba0c1

RESEARCH PRODUCT

Frictional Forces between Strongly Compressed, Nonentangled Polymer Brushes: Molecular Dynamics Simulations and Scaling Theory

subject

description

By means of molecular dynamics simulations and scaling theory we study the response of opposing polymer brushes to constant shear motion under good solvent conditions. Model systems that contain explicit solvent molecules (Lennard-Jones dimers) are compared to solvent-free systems while varying of the distance between the grafted layers and their molecular parameters, chain length and grafting density. Our study reveals a power-law dependence of macroscopic transport properties on the Weissenberg number, W, beyond linear response. For instance, we find that the kinetic friction constant scales as μ ∼ W0.57 for large values of W. We develop a scaling theory that describes our data and previous numerical data including recent experiments. © 2010 American Chemical Society. Fil: Galuschko, A.. Institut Charles Sadron; Francia Fil: Spirin, L.. Johannes Gutenberg Universitat Mainz; Alemania Fil: Kreer, T.. Institut Charles Sadron; Francia Fil: Johner, A.. Institut Charles Sadron; Francia Fil: Pastorino, Claudio. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Wittmer, J.. Institut Charles Sadron; Francia Fil: Baschnagel, J.. Institut Charles Sadron; Francia