This article presents a discussion of two examples of the rheo-optics of flow-induced structure formation in solutions of flexible and semi-rigid chain systems. Polystyrene solutions show shear-thickening, turbidity, and associated dichroism maximization during flow which can be related to the formation of micron-sized aggregates. Hydroxypropylcellulose in acetic acid represents a semi-rigid system which can undergo a conformational change under shear flow which is distinct from the overall molecular ordering. Such changes can be conveniently monitored in terms of the circular birefringence.
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