Transverse cylindrical microdomain orientation in an LC diblock copolymer under oscillatory shear. Macromolecules

The development of oriented microdomain morphol-ogies by shearing lamellar and cylindrical microdomain block copolymers has been studied by many researchers, and observed orientations were found to depend on such variables as temperature (in particular proximity to ODT), strain amplitude, strain rate, mechanical con-trast, chain architecture, and molecular weight.1-10 Good reviews of work in this area are available.11,12 For lamellae and for cylinders, three distinct orientations are possible, viz. parallel, perpendicular, and transverse, discriminated by the orientation of the cylinder long axes and lamellar repeat vector with respect to the flow and flow gradient directions in each case. Processing conditions of lamellar systems have been found that lead to all three types of orientation as well as mixe