Nearest neighbor order in an aligned solution of interacting rod-like micelles

Abstract

Rod-like micelles of hexadecylpyridiniumsalicylate in aqueous solution were aligned by a shear gradient Γ of up to 40 s−1. Small angle neutron diffraction patterns of a solution of 20 mM/ℓ show a pronounced peak in scattering intensity at a momentum transfer of 0.15 nm−1 due to a correlation of the charged micelles. This correlation peak becomes deformed substantially with increasing Γ. A simple model is presented, taking into account an anisotropic change of the pair correlation function. It turns out that the order is reduced in the direction of the vector of velocity v of the sheared liquid and increases perpendicular to this vector.