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Log-periodic oscillations for biased diffusion of a polymer chain in a porous medium

  • V. Yamakov
  • A. Milchev
  • G.M. Foo
  • R.B. Pandey
  • D. Stauffer
Article

Abstract:

A coarse-grained off-lattice bead-spring model is used to reveal the complex dynamics of a polymer chain in a quenched porous medium in the presence of an external field B. The behavior of the mean square displacement (MSD) of the center chain bead and that of the center of mass of the chain as a function of time is studied at different values of the barrier concentration C, the field strength B and the chain length N. In a field, important information on the way in which chains move between obstacles and overcome them is gained from the MSD vs. time analysis in the directions parallel and perpendicular to the flow. Instead of a steady approach to uniform drift-like motion at low C, for sufficiently strong field B we observe logarithmic oscillations in the effective exponents describing the time dependence of the MSD along and perpendicular to field. A common nature of this phenomenon with oscillatory behavior, observed earlier for biased diffusion of tracers on random lattices, is suggested.

PACS. 36.20.-r Macromolecules and polymer molecules - 82.45.+z Electrochemistry and electrophoresis - 87.15.-v Biomolecules: structure and physical properties 

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Copyright information

© EDP Sciences, Springer-Verlag 1999

Authors and Affiliations

  • V. Yamakov
    • 1
  • A. Milchev
    • 1
  • G.M. Foo
    • 3
  • R.B. Pandey
    • 2
  • D. Stauffer
    • 4
  1. 1.Institute for Physical Chemistry, Bulgarian Academy of SciencesBulgaria
  2. 2.Department of Physics and AstronomyUniversity of Southern MississippiHattiesburgUSA
  3. 3.Supercomputing and Visualization Unit, National University of SingaporeSingapore
  4. 4.Institute for Theoretical Physics, Cologne UniversityGermany

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