1996 Volume 39 Issue 1 Pages 112-118
High-polymer aqueous solutions show various interesting flow phenomena in their liquid motions, e.g., non-Newtonian viscosity, the Toms effect, Johnson effect, and effect on jet breakup and elastic effects. Visualization and observation of the polymer chain orientation or alignment under external stress in a fluid flow region are very important in the basic research for the clarification of these phenomena. In this work, polyethylene oxide is used as the polymer additive, and a steady Couette flow region is formed with a rotating disk and a fixed wall. The sample is a thin piece of ice adhered to the end of a round brass base, which is supercooled by liquid nitrogen and fixed into the rotating disk, keeping the end of the surface flush with the disk surface. The ice sample is dehydrated by the freeze-drying method and observed under a microscope. Polymer molecules form a network structure as bundles of polymer chains, and this network state changes with flow shear rate, molecular weight and the concentration of polymer.