W. Mattice
University of Akron, Polymer Science
Bridges between Coarse-grained and Atomistic Descriptions of Polymer Melts
Wayne L. Mattice and Thomas C. Clancy
Institute of Polymer Science, The University of Akron
Dense amorphous polymers exhibit properties on a wide range of
distance and time scales. These broad ranges create problems for their
simulation. Simulations expressed with fully atomistic detail are
limited to phenomena at the short ends of the time and distance
scales. Access to longer time and distance scales is possible with
coarse-grained models, but usually with the loss of a connection with any
particular real system. Bridging methods approach this problem by allowing
the computationally intensive part of the simulation to be performed with a
coarse-grained model, followed by mapping of the equilibrated coarse-grained
model onto a fully atomistic description of the same system. The general
approach taken in our group will be described, followed by illustration with
the application to a specific problem posed by recent experiments by
Mulhaupt's group in Germany, using polypropylene melts. These experiments
show that the miscibility of the melt depends on the stereochemical
composition of the chains contained therein. The challenge to the simulation
is to completely equilibrate the melt, but using a method that accurately
retains the controlling influence of the local structure (stereochemical
composition).
