Universal monomer dynamics of a two-dimensional semi-flexible chain
Abbreviated Journal Title
PERSISTENCE LENGTH; MONTE-CARLO; POLYMERS; MACROMOLECULES; SIMULATION; STIFFNESS; DILUTE; MODEL; DNA; Physics, Multidisciplinary
We present a unified scaling theory for the dynamics of monomers for dilute solutions of semi-flexible polymers under good solvent conditions in the free draining limit. Our theory encompasses the well-known regimes of mean square displacements (MSDs) of stiff chains growing like t(3/4) with time due to bending motions, and the Rouse-like regime t(2 nu/(1+2 nu)) where nu is the Flory exponent describing the radius R of a swollen flexible coil. We identify how the prefactors of these laws scale with the persistence length l(p), and show that a crossover from stiff to flexible behavior occurs at a MSD of order l(p)(2) (at a time proportional to l(p)(3)). A second crossover (to diffusive motion) occurs when the MSD is of order R-2. Large-scale molecular-dynamics simulations of a bead-spring model with a bond bending potential (allowing to vary l(p) from 1 to 200 LennardJones units) provide compelling evidence for the theory, in D = 2 dimensions where nu = 3/4. Our results should be valuable for understanding the dynamics of DNA (and other semi-flexible biopolymers) adsorbed on substrates. Copyright (C) EPLA, 2014
"Universal monomer dynamics of a two-dimensional semi-flexible chain" (2014). Faculty Bibliography 2010s. 5469.