Ordering of cylindrical domains of block copolymers under moving temperature gradient:: Separation of delT-induced ordering from surface-induced ordering

In a previous paper [Mita et al. Macromolecules 2007, 40,5923], we reported that the zone heating method applied to the block copolymer bulk forming hexagonally packed cylindrical (hex-cyl) microdomain Structure enables to develop unique columnar grams macroscopically extended along the temperature gradient (del T) axis and that within the grain hex-cyl has a fixed orientation: Both the cylinder axis and the (100) plane of hex-cyl are normal to the del T axis, and the rotational angle of the cylinder around the del T axis is fixed also. We believe the method involves the ordering under two external fields coupled together: one is a field induced by a glass surface, and the other is a field induced by a moving del T. In this paper, we aim to separate effects of the two fields on the ordering of hex-cyl in order to clarify the effects intrinsic in the moving del T field. For this purpose, we tilt the glass Surface with respect to del T direction by an angle of 45 degrees. Small-angle X-ray scattering studies revealed that the moving del T itself can create the columnar grain texture, independent from the surface-induced ordering effect: The effects of the moving del T field become dominant over those of the glass-surface field with an increase of the distance from the glass surface.