Thermodynamic and Hydrodynamic Properties of Dilute Solutions of Cyclic and Linear Polystyrenes

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The thermodynamic and hydrodynamic properties of cyclic and linear polystyrenes, ranging from 10000 to 180000 molecular weight, in dilute solutions of cyclohexane have been measured by small-angle neutron scattering (SANS) and dynamic light scattering. The diffusion coefficient D(c) was measured at θA2=0as a function of concentration c. The hydrodynamic radii were determined and found to be slightly smaller for cyclic than for linear macromolecules. The slope kD,defined by D(c) = D(0)(1 + kDc), was found to be negative and was, within experimental error, independent of molecular architecture. The molecular weight dependence of the radius of gyration, the hydrodynamic radius, and kDis discussed. © 1987, American Chemical Society. All rights reserved.