Confined thin film diblock copolymer in the presence of an electric field

We have studied theoretically the effect of an external electric field on the equilibrium properties of lamellar and cylindrical assembly in confined diblock copolymers. The critical electric field at which a vertical morphology of lamellae is preferred over a horizontal configuration is found to have only a weak explicit dependence on the plate separation D when D is larger than a few bulk lamellar periods. In the case of the cylindrical morphology, the situation is found to be more complex, with the dimensions of the plates also playing a crucial factor. In both morphologies, the difference between the values of the polymer-plate interfacial tension for each of the two components is found to be a determining factor for the critical field. (C) 2001 American Institute of Physics.