Kinetic pathways of sphere-to-cylinder transition in diblock copolymer melt under electric field.

Phase transition from body-centered-cubic spheres to cylinders in a diblock copolymer melt under an external electric field is investigated by means of real-space dynamical self-consistent field theory. Different phase transition kinetic pathways and different cylindrical domains arrangements of the final phase are observed depending on the strength and direction of the applied electric field. Various transient states have been identified depending on the electric field being applied along [111], [100], and [110] directions. The electric field should be above a certain threshold value in order the transition to occur. A "dynamic critical exponent" of the transition is found to be about 3/2, consistent with other order-order transitions in diblock copolymers under electric field.