Orientation behaviour of AB and ABC block copolymers under large amplitude oscillatory shear flow in bulk and in concentrated solution

Abstract

AbstractFlow alignment in a large amplitude oscillatory shear field of lamellar AB and ABC block copolymers has been studied in bulk and in solution. Flow birefringence and 2D small-angle X-ray scattering were used to monitor the orientation. Qualitatively similar orientation behaviour was found for the diluted and the bulk AB block copolymer. While in AB diblock copolymers there is only one interface between the different blocks which may influence the orientation behaviour, in ABC triblock copolymers there are two interfaces within the macromolecule. It will be shown that the introduction of a third block leads to a quite different orientation behaviour in comparison to the AB system. In the lamellar diluted ABC system always the parallel orientation dominates, but it occurs in coexistence with the perpendicular and transverse orientations.