Dissymmetry coefficient

The root-mean-square distance Vr separating the ends of the polymer chain is a convenient measure of its linear dimensions. The dissymmetry coefficient will be unity for (VrV 0< l and will increase as this ratio increases. 

Typical results of lightscattering measurements are shown in Figs. 47 and 48 for polystyrene fractions of medium and of very high molecular weight, respectively. The small dissymmetry correction for the former was calculated from the measured dissymmetry coefficient 45°( l-2) using Eqs. (31) and (32). 

Table Dissymmetry coefficient Zd and [P(90°)]-1 for different particle shapes Coil Rod Sphere...

It is seen from Fig. 4.15(c) that (i) the forward scatter exceeds the backward scatter, that is, the dissymmetry coefficient, z, exceeds 1, and (ii) the forward scatter at zero angle (9 — 0°) is the same whether interference effects are present or not. It is therefore easy to decide whether interference effects must be considered or not from experimentally observed values of Rg and if the two quantities Rg and differ significantly from... 

Table P4.19.1 Dissymmetry coefficient versus concentration for polystyrene sample in Problem 4.17...

Corresponding to this value of dissymmetry coefficient one obtains from Fig. 4.18 the ratio < / = 0-30. Having found < /A, u may be computed... 

Figure 9-8. Dependence of the dissymmetry coefficient z of scattered light at angles of 45° and 135° on the ratio of >/X for spheres (sph), unimolecular random coils cm)y polymolecular (Mn) = 2) random coils Cp), and rods (r). Here Xo is the wavelength of light in the medium of refractive index n, and D corresponds to the diameter of the spheres, the length of the rods, and the chain end-to-end distance of coiled macromolecules.

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