抄録
The effects of simple shear flow on concentration fluctuations in polymer solutions are investigated as a function of S, T, c, and N by the flow light scattering method. Here, S is the shear rate, T the temperature, c the polymer concentration, and N the degree of polymerization of the polymer. Over the range of the concentration studied in this experiment (a semidilute regime covering c⁄c*=4 to 20, where c* is the overlap concentration), strong shear-enhanced concentration fluctuations were observed above a certain critical shear rate Sc. For S>Sc, the integrated scattered intensity (Remark: Graphics omitted.) in the direction perpendicular to the flow increases at least by two orders of magnitude compared to that of the homogeneous solution. The scattering patterns observed for S>Sc have two main chracteristics: (i) they are very diffuse, extending up to high scattering vectors and (ii) they have a sharp and strong destructive interference in the direction perpendicular to the flow.
