せん断流動場におかれた高分子水溶液中のポリマ鎖の可視化に関する一実験

抄録

High-polymer aqueous solutions show various interesting phenomena in their liquid motions, i.e., non-Newtonian viscosity, Toms effect, Johnson effect, effect on jet breakup, elastic effects and so on. Visualization and observation of the polymer chain orientation or alignment under external stress in a fluid flow region will be very important issues in the basic research for the clarification of these phenomena. In this report, polyethylene oxide is used as the polymer additive, and steady Couette flow region is formed with a rotating disk and a fixed wall. The sample is a thin piece of ice adhered on the end of a round brass model, which is supercooled by liquid air 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 using a microscope. Polymer molecules build up a network structure in the bundle of polymer chains, and this network state changes with flow shear rate, molecular weight and the concentration of polymer.