|
Authors
|
R. Descas, J.-U. Sommer and A. Blumen
|
|
Title
|
Dynamical scaling of single chains on adsorbing substrates: Diffusion processes
|
|
Date
|
01.04.2005
|
|
Number
|
111
|
|
Abstract
|
We study the dynamics of tethered chains of length N on adsorbing surfaces, considering the dilute case; for this we use the bond fluctuation model and scaling concepts. In particular, we focus on the mean-square displacement of single monomers and of the center of mass of the chains. The characteristic time tau of the fluctuations of a free chain in a good solvent grows as tau~Na, where the coefficient a obeys a=2nu+1. We show that the same coefficient also holds at the critical point of adsorption. At intermediate time scales single monomers show subdiffusive behavior; this concurs with the behavior calculated from scaling arguments based on the dynamical exponent a. In the adsorbed state tau[perpendicular], the time scale for the relaxation in the direction perpendicular to the surface, becomes independent of N; tau[perpendicular] is then the relaxation time of an adsorption blob. In the direction parallel to the surface the motion is similar to that of a two-dimensional chain and is controlled by a time scale given by tau||~N2nu2+1L2Deltanu/nu, where nu2 is the Flory exponent in two dimensions, nu is the Flory exponent in three dimensions, and Deltanu=nu2nu. For the motion parallel to the surface we find dynamical scaling over a range of about four decades in time.
|
|
Publisher
|
Journal of Chemical Physics
|
|
Wikidata
|
|
|
Citation
|
Journal of Chemical Physics 122 (2005) 134903-134913
|
|
DOI
|
https://doi.org/10.1063/1.1868556
|
|
Tags
|
|
