89 research outputs found
Diffusive Spreading of Chainlike Molecules on Surfaces
We study the diffusion and submonolayer spreading of chainlike molecules on
surfaces. Using the fluctuating bond model we extract the collective and tracer
diffusion coefficients D_c and D_t with a variety of methods. We show that
D_c(theta) has unusual behavior as a function of the coverage theta. It first
increases but after a maximum goes to zero as theta go to one. We show that the
increase is due to entropic repulsion that leads to steep density profiles for
spreading droplets seen in experiments. We also develop an analytic model for
D_c(theta) which agrees well with the simulations.Comment: 3 pages, RevTeX, 4 postscript figures, to appear in Phys. Rev.
Letters (1996
Dynamics and Scaling of 2D Polymers in a Dilute Solution
The breakdown of dynamical scaling for a dilute polymer solution in 2D has
been suggested by Shannon and Choy [Phys. Rev. Lett. {\bf 79}, 1455 (1997)].
However, we show here both numerically and analytically that dynamical scaling
holds when the finite-size dependence of the relevant dynamical quantities is
properly taken into account. We carry out large-scale simulations in 2D for a
polymer chain in a good solvent with full hydrodynamic interactions to verify
dynamical scaling. This is achieved by novel mesoscopic simulation techniques
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