Gyroid-to-cylinder transition in a diblock copolymer melt under an electric field is studied by real-space dynamical self-consistent-field theory. Starting from an equilibrium gyroid structure, we apply an electric field along [111], [11̄0], and [112̄] directions of the conventional unit cell of the gyroid structure. Under sufficiently high value of the electric field, an epitaxial transition to cylinders occurs. Contrary to the case of a similar transition under the shear flow, we observe 5-fold connections as intermediates in the transition. We found a critical behavior of the lifetime of the initial gyroid structure, which can be accounted for using the mean-field argument. Numerically obtained scattering function explains the unclarified intermediates experimentally observed in the thermal relaxation of a sheared gyroid.

Using self-consistent-field simulation, a perforated lamella (PL) is investigated under an applied electric field. The perforated lamella is obtained by confining a cylinder-forming diblock copolymer melt in a thin film with a thickness of the spacing between cylinders in the bulk equilibrium state. Upon application of an electric field, the perforated lamella transforms to laying or standing cylinders depending on the direction of the 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.