Implicit and explicit solvent models for the simulation of a single polymer chain in solution: Lattice Boltzmann vs Brownian dynamics - Condensed Matter > Soft Condensed MatterReport as inadecuate




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Abstract: We present a comparative study of two computer simulation methods to obtainstatic and dynamic properties of dilute polymer solutions. The first approachis a recently established hybrid algorithm based upon dissipative couplingbetween Molecular Dynamics and lattice Boltzmann LB, while the second isstandard Brownian Dynamics BD with fluctuating hydrodynamic interactions.Applying these methods to the same physical system a single polymer chain in agood solvent in thermal equilibrium allows us to draw a detailed andquantitative comparison in terms of both accuracy and efficiency. It is foundthat the static conformations of the LB model are distorted when the box lengthL is too small compared to the chain size. Furthermore, some dynamic propertiesof the LB model are subject to an $L^{-1}$ finite size effect, while the BDmodel directly reproduces the asymptotic $L \to \infty$ behavior. Apart fromthese finite size effects, it is also found that in order to obtain the correctdynamic properties for the LB simulations, it is crucial to properly thermalizeall the kinetic modes. Only in this case, the results are in excellentagreement with each other, as expected. Moreover, Brownian Dynamics is found tobe much more efficient than lattice Boltzmann as long as the degree ofpolymerization is not excessively large.



Author: Tri T. Pham, Ulf D. Schiller, J. Ravi Prakash, Burkhard Duenweg

Source: https://arxiv.org/







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