Pattern formation in driven copolymer systems

The microphase separation of symmetric diblock copolymers in the presence of an external force field is simulated by means of a cell dynamical system model. It is found that the pattern formation is greatly affected by the presence of the field and by the type of boundary conditions considered. With hard wall boundary conditions and a small applied field the formation of well ordered lamellae, parallel to the wall, is observed. For a system with periodic boundary conditions the lamellae are oriented parallel to the external field.