Phase separation of polymer blends under shear field

The effect of shear flow on phase separation in critical polymer blends has been studied. For a low-molecular-weight blend, the response is in good agreement with the theoretical predictions of Onuki and Kawasaki. The breakup of large-scale critical fluctuations by the flow leads to a drop in the temperature T-c at which phase separation begins. For a high-molecular-weight blend, the data suggest that the mode-coupling contribution to the decay rate of composition fluctuations is significant in both the miscible and immiscible phases. However, the lack of change of structure factor in the vorticity direction implies that there is no apparent shear induced shift in T-c.