Hydrodynamic mobilities in a bar-chain polymer model

We consider hydrodynamic interactions in a novel polymer model, in which classic beads are replaced by cylindrical segments corresponding to a fraction of a persistence length. Each segment is modeled as a line of spherical beads. The effect of a neighboring bead or segment on the mobility of the segment of interest is calculated. Hydrodynamic interactions are treated with generalizations, developed by Kynch (1959) and by Mazur and van Saarloos (1982) of the Oseen and Rotne–Prager hydrodynamic interaction tensors. We find that the hydrodynamic interactions between two segments, as they affect the mobility of a given segment, are with a minor exception not very different from the interactions between two beads, especially when the two segments are even modestly separated. At the level of approximation of bead–spring models of polymer coils, we thus do not find evidence that it is advantageous to replace sphere–sphere hydrodynamic interaction tensors with more elaborate segment–segment hydrodynamic interaction tensors. •Polymer hydrodynamic units were modeled as cylinders...rigid lines of spheres.•Hydrodynamic interactions were included through the (a/r)7 level.•Modeling hydrodynamic units as cylinders rather than spheres gives little advantage.