  The self-assembly behaviour of a diblock copolymer-diblock copolymer mixture
under an oscillating shear field is investigated via cell dynamics simulation.
The results indicate that the macrophase separation of the composite system is
accompanied by the corresponding microphase separation induced by the
oscillating shear field. With an increase in the shear frequency, the AB phase
changes from a tilted layered structure to a parallel layered structure, and
finally to a vertical layered structure. The CD phase transforms from the
initial concentric ring into a parallel layer in the ring and then into a
parallel layered structure; thus, the system finally forms a layered structure
of the AB phase (vertical layer) and CD phase (parallel layer) perpendicular to
each other. To verify the phase transition, the dynamic evolution of the domain
size at different shear frequencies is analysed. The ordered phase transition
with an increase in the oscillating shear field varies when the initial
composition ratio of the system is changed. This conclusion provides a valuable
guidance for the formation and transformation of ordered structures in
experiments.
