Block Copolymer Domain Reorientation in an Electric Field: An in-Situ Small-Angle X-ray Scattering Study

Using in-situ small-angle X-ray scattering, the electric field induced orientation of symmetric block copolymers of polystyrene and polyisoprene was investigated. Alignment of the lamellar microdomains parallel to the electric field was achieved within minutes to a high degree of orientation. Analysis of the scattering patterns indicated that, during alignment of the lamellar microdomains, the material goes through an intermediate state with substantially reduced long-range order. After orientation, the sample consists of many small grains with the lamellae being oriented parallel to the electric field and a random orientation in the plane perpendicular to the field.