Crystallization of a Polymer on a Surface
J. Chem. Phys. 109, 10033-10041 (1998)
Jonathan P. K. Doye and Daan Frenkel
Abstract
We have studied the structure and free energy landscape of a semi-flexible lattice-polymer
in the presence of a surface.
At low temperatures coexistence of two-dimensional integer-folded crystals is observed.
As the temperature is increased there is a transition from these
crystalline configurations to a disordered coil adsorbed onto the surface.
The polymer then gradually develops three-dimensional character at higher temperatures.
We compute the free energy as a function of increasing crystallinity and
compare with the free energy profiles assumed by the Lauritizen-Hoffman surface nucleation theory
of polymer crystallization.
Our free energy profiles exhibit a `sawtooth' structure associated with the successive
formation of chain folds.
However, in the early stages of crystallization our profiles significantly deviate
from those assumed by surface nucleation theory because the initial nucleus is not
a single stem but two incomplete stems connected by a fold.
This finding has significant implications for the theoretical description of polymer crystallization.
The full paper is available from
JCP Online and the
Los Alamos preprint server
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