Effect of shear on the symmetric diblock copolymer/nanorod mixture: A dissipative particle dynamics study

The phase behaviours of lamellar diblock copolymer/nanorod composite under steady shear are investigated using dissipative particle dynamics. We consider a wide range of nanorod concentrations, where nanorods each have a preferential affinity to one of blocks. Our results suggest that shear not only aligns the orientations of diblock copolymer templates and nanorods towards flow direction, but also regulates the distribution of nanorods within polymer matrix. Meanwhile, the shear-induced reorientation and morphology transitions of systems also significantly depend on the nanorod concentration. At certain nanorod concentrations, the competitions between shear-induced polymer thinning and nanorods dispersion behaviours determine the phase behaviours of composites. For high nanorod concentrations, no morphology transition is observed, but reorientation is present, in which the sheared nanorods are arranged into hexagonal packing arrays. Additionally, the orientation behaviour of nanorods is determined directly by the applied shear, also interfered by the shear-stretched copolymer molecules.