Investigating microstructure of concentrated suspensions of anisotropic particles under shear by small angle neutron scattering

he microstructure of dense suspensions of anisotropic particles that are ordered at rest is explored nder shear as a function of particle anisotropy and shear rate using small angle neutron scattering. or suspensions containing spheres and mildly anisotropic heteronuclear dicolloids, after reshearing, long-range order is present in the form of randomly stacked hexagonally close packed ayers. As the shear rate is increased, long-range directional order is lost. At even higher shear ates, long-range order is re-established in the form of hexagonally packed layers sliding over one nother. Suspensions of ordered homonuclear dicolloids are polycrystalline at rest, and as the shear ate is increased, sliding hexagonally packed layers develop while at larger shear rates long-range rder is lost. These results demonstrate surprisingly large effects of shear on the microstructures of uspensions containing particles with small changes in anisotropy. © 2007 The Society of heology. DOI: 10.1122/1.2716452