Atactic polystyrene birefringence

Figure J. a. The opposed jets. The polymer solution is sucked into the jets along the symmetry axis, o represents the stagnation point in the center of the flow field, b. The flow field visualized by light scattered at 90° from tracer particles, c, A birefringent line between the jets for a 0.1% solution of atactic polystyrene (a-PS). d. The perturbed flow field during flare formation in a semiddute polyethylene oxide solution.

Figure 2. Experimentally determined flow-induced birefringence vs. strain rate for atactic polystyrene. The maximum value of birefringence is 1.15 x 10, which corresponds to an optical retardation of 27 nm for a cell depth of 1.8 mm 0.1% solution. Mu, 5.5 X 10 in decahydronaphthalene).

WANS experiments were performed in order to investigate the liquid state of atactic polystyrene. It was found that PS undergoes both a reversible and an irreversible structural change at a temperature which corresponds to Tn, the liquid-liquid transition. These results plus earlier results on birefringence are interpreted in terms of a structural model presented by Mitchell and Windle. 

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