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Complex Fluids 2007
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Scale Bridging Simulations of Soft Matter
CSIC Building (#406),
Seminar Room 4122.
Directions: home.cscamm.umd.edu/directions
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Scale Bridging Simulations of Soft Matter
Professor
Kurt Kremer
Max-Planck Institut für Polymerforschung
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Abstract:
The relation between atomistic structure,
architecture, molecular weight and material
properties is a basic concern of modern soft
material science. The longstanding aim by now goes
far beyond standard properties of bulk materials. A
typical additional focus is on surface interface
aspects or the relation between structure and
function in nanoscopic molecular assemblies. This
all implies a thorough understanding on many length
and correspondingly time scales ranging from (sub)atomic
to macroscopic. At this point computer simulations
are playing an increasingly important, if not the
central role. Traditionally simulations have been
separated in two main groups, namely simplified
models to deal with generic or universal aspects,
i.e. critical exponents, of polymers and those
employing classical force field simulations with
(almost) all atomistic detail, i.e. for the
diffusion of small additives in small "sample. Still
characteristic problems, which require huge systems
and or long times in combination with a chemistry
specific model, cannot be tackled by these methods
alone. More recently with the development of scale
bridging or multi scale simulation techniques, these
different approaches have been combined into an
emerging rather powerful tool. It is the purpose of
this talk to give a few examples of how such an
approach, which combines ab initio quantum level
calculations, force field simulations as well as
coarse grained molecular dynamics simulations in a
systematic manner, can be used to understand
specific material properties. Questions considered
range from surface morphologies of polymer melts
close to a metal surface experiencing specific
interactions to the classical problem of
entanglements and also to simplified models of
membranes. By using a mapping scheme, which allows
for a scale bridging in both the coarsening as well
as the detailing direction, new classes of problems
can be tackled by simulations. Some recent attempts
to construct a small molecular tool set for such
simulations as well as first steps towards an
adaptive scheme will be mentioned shortly. To
progress further eventually adaptive schemes have to
be developed. First attempts towards this direction
will be presented as well.
[slides] |
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