It gives us great pleasure to announce that this paper has been selected to receive the 8th Feng Xinde Polymer Prize for the Best Chinese Paper published in the journal Polymer during 2013.
Instead of using free energy, we directly balanced confinement and hydrodynamic forces (fc = kBT/ξ and fh = 3πηule) on individual “blobs” to obtain a unified description of how polymer chains with different topologies (linear, star and branched) pass through a cylindrical pore with a diameter of D, much smaller than its size, under a flow rate (q), where kB, T, η, ξ, u (=q/D2), and le are the Boltzmann constant, absolute temperature, viscosity, “blob” diameter, flow velocity, and the blob's effective length along the flow direction, respectively; and each “blob” is defined as a maximum portion of the confined chain whose confinement free energy becomes of order thermal energy (kBT). Namely, using fc = fh, we easily locate at which minimum (critical) flow rate (qc) polymer chains with different topologies are able to pass through the pore without priori consideration of chain topology, i.e., a general description, qc/qc,linear = (D/ξ)2, where qc,linear equals [kBT/(3πη)](ξ/le). The only thing left here is to find ξ for each topology. Obviously, for a confined linear chain, ξlinear = D. For a confined star chain, ξstar = [2/(f + |f−2fin|)]1/2D, where f is arm number and fin is the number of arms first inserted into the pore; and for a branched chain, ξbranch = (D/a)α’Nt,Kuhnβ’Nb,Kuhnγ’, where a is the size of one Kuhn segment, Nt,Kuhn and Nb,Kuhn are respectively the numbers of Kuhn segments of the entire branched chain and the subchain between two neighboring branching points; and the three constant exponents (α′, β′ and γ′) are directly related to the well-known Flory's scaling exponents between the chain size and both Nt,Kuhn and Nt,Kuhn.
This paper was originally published in Polymer 55 (5) pp.1463-1465.
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