Delayed slip after step strains in highly entangled polystyrene solutions

摘要: Apparent slip within a few micrometers of glass surface is visualized with microscope using small spheres as tracers suspended in highly entangled 20% solution polystyrene molecular weight 8.42 million, confined between plates plane Couette device. After step shears 0.5–5 strain units, particles each move by 70–500 μm, enough to unload more than half the imposed shear at intermediate strains. The displacement, when plotted logarithmically against time, show peculiar ‘‘kink’’ vicinity ‘‘Rouse’’ time 100 s, similar kink reported for stress. These results that rheological properties solutions are produced an effective phenomenon occurs either wall or thin disentanglement layer near it.