  Using the self-consistent field approach, the effect of asymmetry of the coil
block on the microphase separation is focused in ABC coil-rod-coil triblock
copolymers. For different fractions of the rod block $f_{\text B}$, some stable
structures are observed, i.e., lamellae, cylinders, gyroid, and core-shell
hexagonal lattice, and the phase diagrams are constructed. The calculated
results show that the effect of the coil block fraction $f_{\text A}$ is
dependent on $f_{\text B}$. When $f_{\text B}=0.2$, the effect of asymmetry of
the coil block is similar to that of the ABC flexible triblock copolymers; When
$f_{\text B}=0.4$, the self-assembly of ABC coil-rod-coil triblock copolymers
behaves like rod-coil diblock copolymers under some condition. When $f_{\text
B}$ continues to increase, the effect of asymmetry of the coil block reduces.
For $f_{\text B}=0.4$, under the symmetrical and rather asymmetrical
conditions, an increase in the interaction parameter between different
components leads to different transitions between cylinders and lamellae. The
results indicate some remarkable effect of the chain architecture on
self-assembly, and can provide the guidance for the design and synthesis of
copolymer materials.
