Self-assembly of symmetric diblock copolymer AB/homopolymer A or C blends confined in spherical nanopores is studied by using a simulated annealing method.Three kinds of blends with different homopolymer chain lengths are investigated.Simulation results show that the self-assembly behavior of the blends depends on the content of the homopolymer

the chain length of the homopolymer

the degree of confinement (characterized by D/L0

where D is the diameter of the spherical nanopore and L0 is the period of the bulk lamellar phase of symmetric diblock copolymer)

and the interaction strength between A-C monomers.With the variation of the content of homopolymer and the degree of confinement

the blends exhibit a variety of morphologies and morphological transitions.The observed morphologies include onion-like structures (with both concentric lamellae and nonconcentric lamellae)

cage-like structures

deformed dome-like structures

helices or stacked toroids

a disk-like layer and spherical structures.Furthermore

the obtained simulation results also show that both the chain length of the homopolymer and the A-C interaction strength have a large effect on the compatibility of the blends.When the A-C interaction strength is relatively weak

the shorter the chain length of homopolymer

the better the compatibility of the blend

and the corresponding structures occur at a slightly smaller value for the homopolymer content.When the interaction strength between the A-C monomers is strong enough

the effects caused by homopolymer chain length become less pronounced and eventually disappear.In this case

the blend has a good compatibility.The simulation results are consistent with recent experimental results of similar systems.