ORDERING PHENOMENA OF STAR POLYMER-SOLUTIONS APPROACHING THE THETA-STATE

The liquid-state ordering phenomena of a semidilute polybutadiene 64-a rm star polymer solution were investigated by small-angle neutron scat tering. For this purpose, we used deuterated 1,4-dioxane, which is a X i solvent for the star at 31.5 degrees C. Its quality was modified by varying the temperature in the range between 40 degrees C and 80 degre es C. Besides a swelling of the star, with increasing temperature the development of a strong correlation peak was observed in the experimen t. The experimental data were described theoretically by employing an effective pair potential between stars which was introduced earlier by Mewis et al. [J. Mewis, W. J. Frith, T. A. Strivens, and W. B. Russel , AIChE J. 35, 415 (1989)]. [S1063-651X(98)13611-5].