  The impact of complex media on the dynamics of active swimmers has gained a
thriving interest in the research community for their prominent applications in
various fields. This paper investigates the effect of viscoelasticity on the
dynamics and aggregation of chemically powered sphere-dimers by using a
coarse-grained hybrid mesoscopic simulation technique. The sphere-dimers
perform active motion by virtue of the concentration gradient around the
swimmer's surface, produced by the chemical reaction at one end of the dimer.
We observe that the fluid elasticity enhances translational and rotational
motion of a single dimer, however for a pair of dimers, the clustering in a
particular alignment is more pronounced. In case of multiple dimers, the
kinetics of cluster formation along with their propulsive nature are presented
in detail. The key factors influencing the enhanced motility and the
aggregation of dimers are the concentration gradients, hydrodynamic coupling
and the microstructures present in the system.
