  Star polymers with magnetically functionalized end groups are presented as a
novel polymeric system whose morphology, self-aggregation, and orientation can
easily be tuned by exposing these macromolecules simultaneously to an external
magnetic field and to shear forces. Our investigations are based on a
specialized simulation technique which faithfully takes into account the
hydrodynamic interactions of the surrounding, Newtonian solvent. We find that
the combination of magnetic field (including both strength and direction) and
shear rate controls the mean number of magnetic clusters, which in turn is
largely responsible for the static and dynamic behavior. While some properties
are similar to comparable non-magnetic star polymers, others exhibit novel
phenomena; examples of the latter include the breakup and reorganization of the
clusters beyond a critical shear rate, and a strong dependence of the
efficiency with which shear rate is translated into whole-body rotations on the
direction of the magnetic field.
