Anisotropic phase separation kinetics in a polymer blend solution following cessation of shear studied by light scattering

TitleAnisotropic phase separation kinetics in a polymer blend solution following cessation of shear studied by light scattering
Publication TypeJournal Article
Year of Publication1992
AuthorsWaldow, Dean, Nakatani Alan I., and Han Charles C.
JournalPolymer
Volume33
Issue21
Pagination4635-8
AbstractA light scattering instrument capable of monitoring the scattering from samples under the influence of a simple shear field is constructed. The app. consists of transparent cone-and-plate fixtures. and a two-dimensional charge coupled device array detector. The detector unit is also capable of measuring the scattering patterns as a function of time. The phase sepn. kinetics of an 8% soln. of a polystyrene-polybutadiene (50:50) blend in dioctyl phthalate following cessation of a steady shear is monitored with this instrument. The sample is two-phase in the quiescent state and the applied shear is sufficient to suppress all scattering obsd. from the quiescent sample (shear-induced mixing). The evolution of the scattering profiles following cessation of shear is quite different parallel and perpendicular to the original flow direction. In the normal direction, a spinodal growth and coarsening mechanism similar to that obsd. in temp. quench expts. is obsd. In the parallel direction, a different mechanism is followed.