Neutron scattering from charge stabilized suspensions undergoing shear

Abstract

Small angle neutron scattering(SANS) is used to investigate the local order in aqueous, charge stabilized suspensions of 103 Å diameter polystyrene latexspheres at ∼14 wt. % solids. These samples which evidence a close packed close packed structure in equilibrium are observed to undergo a transition to an amorphous order when sustaining a sufficiently large and steady shear. The shear melting phenomonology is different from that observed by light scattering for very dilute (0.16 wt. % solids) suspensions of polystyrene particles which form bcc lattices in equilibrium. Furthermore, neutron scattering reveals more detail than light scattering for concentrated suspensions and indicates a larger degree of three-dimensional ordering under steady shear flow than is implied by sliding layer models for similar systems.