Mesoscopic crystallography of shear-aligned soft materials

Abstract

The development of a novel device for examining the three-dimensional structure of shear-aligned soft materials using small-angle X-ray scattering is reported. Following alignment via oscillatory shear, the shear plates are fixed together and the whole assembly mounted on a miniature goniometer placed within the oven of the rheometer. It is then possible to perform two-axis crystallography, rotating around the shear direction, and tilting with respect to this axis. Preliminary results are presented that highlight the information on aligned block copolymer nanostructures that can be accessed using the goniometer. Diffraction patterns obtained from a shear-aligned hexagonal close-packed micellar structure formed in an aqueous solution of an amphiphilic diblock are discussed, as well as those of the metastable hexagonal perforated lamellar structure formed in a diblock copolymer melt. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved.