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Polymer scaling and dynamics in steady-state sedimentation at infinite Péclet number

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Lehtola, V.
dc.contributor.author Punkkinen, O.
dc.contributor.author Ala-Nissilä, Tapio
dc.date.accessioned 2015-04-28T09:44:04Z
dc.date.available 2015-04-28T09:44:04Z
dc.date.issued 2007
dc.identifier.citation Lehtola, V. & Punkkinen, O. & Ala-Nissilä, Tapio. 2007. Polymer scaling and dynamics in steady-state sedimentation at infinite Péclet number. Physical Review E. Volume 76, Issue 5. P. 051802/1-7. ISSN 1539-3755 (printed). DOI: 10.1103/physreve.76.051802. en
dc.identifier.issn 1539-3755 (printed)
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/15791
dc.description.abstract We consider the static and dynamical behavior of a flexible polymer chain under steady-state sedimentation using analytic arguments and computer simulations. The model system comprises a single coarse-grained polymer chain of N segments, which resides in a Newtonian fluid as described by the Navier-Stokes equations. The chain is driven into nonequilibrium steady state by gravity acting on each segment. The equations of motion for the segments and the Navier-Stokes equations are solved simultaneously using an immersed boundary method, where thermal fluctuations are neglected. To characterize the chain conformation, we consider its radius of gyration RG(N). We find that the presence of gravity explicitly breaks the spatial symmetry leading to anisotropic scaling of the components of RG with N along the direction of gravity RG,∥ and perpendicular to it RG,⊥, respectively. We numerically estimate the corresponding anisotropic scaling exponents ν∥≈0.79 and ν⊥≈0.45, which differ significantly from the equilibrium scaling exponent νe=0.588 in three dimensions. This indicates that on the average, the chain becomes elongated along the sedimentation direction for large enough N. We present a generalization of the Flory scaling argument, which is in good agreement with the numerical results. It also reveals an explicit dependence of the scaling exponents on the Reynolds number. To study the dynamics of the chain, we compute its effective diffusion coefficient D(N), which does not contain Brownian motion. For the range of values of N used here, we find that both the parallel and perpendicular components of D increase with the chain length N, in contrast to the case of thermal diffusion in equilibrium. This is caused by the fluid-driven fluctuations in the internal configuration of the polymer that are magnified as polymer size becomes larger. en
dc.format.extent 051802/1-7
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher American Physical Society (APS) en
dc.relation.ispartofseries Physical Review E en
dc.relation.ispartofseries Volume 76, Issue 5
dc.rights © 2007 American Physical Society (APS). http://www.aps.org en
dc.subject.other Physics en
dc.title Polymer scaling and dynamics in steady-state sedimentation at infinite Péclet number en
dc.type A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä fi
dc.description.version Peer reviewed en
dc.rights.holder American Physical Society (APS)
dc.contributor.school Perustieteiden korkeakoulu fi
dc.contributor.school School of Science en
dc.contributor.department Teknillisen fysiikan laitos fi
dc.contributor.department Department of Applied Physics en
dc.subject.keyword polymers en
dc.subject.keyword sedimentation en
dc.subject.keyword hydrodynamics en
dc.identifier.urn URN:NBN:fi:aalto-201504282452
dc.type.dcmitype text en
dc.identifier.doi 10.1103/physreve.76.051802
dc.type.version Final published version en

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