Mat-1.600 Laskennallisen tieteen ja tekniikan seminaari

24.2.  14.15  U322


Multiscale modeling in soft matter physics: Advances
and problems in bridging the time- and length-scale gap
Mikko Karttunen, Laskennallisen tenkiikan laboratorio

Mesoscopic phenomena in soft matter and biological systems, e.g. colloids and biomembranes, generally involve some form of coupling between different characteristic time- and length-scales. Computational modeling of such multi-scale effects requires new methodology applicable beyond the realm of traditional techniques such as ab initio and classical molecular dynamics. In this talk I present a promising coarse-graining strategy for linking micro- and mesoscales in soft matter and biological systems. The approach is based on effective pairwise interaction potentials obtained from detailed atomistic molecular dynamics (MD) simulations, which are then used in coarse-grained dissipative particle dynamics simulations (DPD). A simple aqueous NaCl solution is used as a test case. With the same computational effort we are able to simulate systems of at least one order of magnitude larger as compared to the MD simulations. The results from the MD and DPD simulations are found to be in excellent agreement.
In the second part of my talk, I will discuss some of the challenges related to coarse graining biological systems and some caveats related to the underlying molecular dynamics simulations. MD simulations of fully hydrated pure dipalmitoylphosphatidylcholine (DPPC) bilayer are used as an example.