Cell dynamics simulations of shear-induced alignment and defect annihilation in stripe patterns formed by block copolymers

The effect of large amplitude oscillatory shear on two-dimensional stripe patterns formed by block copolymers was investigated using cell dynamics simulations. A global orientational order parameter S and a correlation function for stripe normals $G\left(\mathbf{r}-{\mathbf{r}}^{\prime }\right)$ were used to characterize the degree of stripe orientation under shear. The kinetics of stripe alignment, quantified by S, at various shear and quench conditions were studied as a function of strain amplitude, shear frequency, and temperature. The mechanisms of shear alignment and defect annihilation were investigated. A critical shear condition for complete alignment of stripes along the shear direction was also identified.