ORDERED PHASE OF PLATE-LIKE PARTICLES IN CONCENTRATED DISPERSIONS

The coexistence of two phases in concentrated dispersions of monodispe rsed platelike particles is reported. Small-angle neutron diffraction has been used to identify a highly ordered phase which coexists at equ ilibrium with a less ordered, less dense phase. The interparticle inte ractions were Varied by adjusting the salt concentration, and this inf luenced the concentration at which the phase transition occurred. Colu mnar or layer structures which could account for the observed diffract ion pattern from the ordered phase are discussed.