The object of this study is to confirm the molecular theory on the solution of the rigid rodlike polmers by analyzing experimentally the transient flow birefringence of the collagen solutions.
By using the PMFB system, flow birefringence measurements can be performed in transient flow conditions. Birefringence and orientation angle of sample can be abtained simultaneously in experimental run. As a sample, acid-soluble calf skin collagen solution was used at various concentration level.
Steady birefringence increases as both concentration and shear rate increase. Following the inception of flow, birefringence increases with time but its overshoot is not detected. From this, collagen can be considered as one of a rodlike polymers.
Following the cessation of simple shear flow, birefringence relaxation changed with the concentration but it was independent of shear rate. Rotational diffusion constant rapidly decreased as the concentration increases arround c = 5 mg/ml, which fits Doi's theoretical prediction. The reason is that molecular motion of polymer chains is severely restricted by neighboring polymer chains, in the region of concentration.
