Phase diagram under shear

For many applications the phase behavior under shear has a great importance, e.g. homogenous solutions should not phase separate during a mechanical handling, whereupon high shear rates exist.
One can find the phenomenon of the shear induced phase separation or the shear induced homogenization of a two-phase system. That means clear solutions can get turbid by shaking and vice versa.
For the determination of these properties a rheometer with special cylindric measurement geometry is used. A laser beam passes a glass window of the measuring cup, afterwards the sample and is reflected at the measuring body and passes the sample a second time. The clearing off or the turbidity of the solution is detected by means of the transmission of the laser intensity via photodiodes.

 

Schema of the shear cell