SMALL-ANGLE SCATTERING OF POLARIZED-LIGHT - VI - SPHERE DOUBLETS AT REST AND DURING SHEAR

The polarized or depolarized light scattering by well-defined monodisp ersed sphere doublets is investigated. ?Two configurations of doublets are studied. In the first (at rest) the doublets are randomly oriente d in a plane, in the second the doublets are oriented in a preferred d irection. This is achieved by submitting a suspension of doublets to a shear flow. The scattering patterns are compared to two theoretical p redictions based on simplified geometries. In the first approach, the doublet is approximated by two interpenetrating spheres scattering ind ependently, whereas in the second, an ellipsoid geometry is used. A go od qualitative comparison is obtained. However, the RV and VH patterns of a randomly dispersed suspension are not similar. The observation o f the flow of a doublet suspension in shear shows that the doublets ar e spiraling around the vorticity axis. (C) 1998 John Wiley & Sons, Inc .