Radii of gyration Rg and hydrodynamic radii Rh of star-shaped polystyrenes with different arm numbers and their arm polymers were measured in toluene solution by static and dynamic light scattering. Rh depends on the number of arms f stronger than Rg. The ratios g~=Rg(star)/Rg(arm) and g~ = Rh (star)/Rh (arm) were compared with other experimental and computer simulation results to examine the universality of these ratios. Universality of the relation of gg versus number of arms f is confirmed. No clear indication of failure of g~ in universality is observed, and it was suggested that g~ is not sensitive to systems. Experimental results were also compared with available theories. The renormalized two-parameter theory by Douglas and Freed for static quantities gg and gA (= A2(star)/A2(linear), where A2 is the second virial coefficient) reproduces the experimental data very well at lower fs and agreement in g~ is excellent over a wide range of f.
Посилання на статтю:
Arm-number dependence of dimensions of star-shaped polystyrene in a good solvent / A. Takano, M. Okada* and T. Nose // Polymer. – 1992. – Vol 33. – P. 783-788.