Viscosity Zimm plot

Fig. 9.— Double Log Plots of (a) Intrinsic Viscosity, (b) the Reciprocal of the Diffiision Coefficient, and (c) Sedimentation Coefficient Data versus Molecular Weight for Human Cervical Mucins. [Key and O, whole mucins and , subunits and A, T-domains. Molecular weights determined from Zimm plots (filled symbols) or the Svedbeig equation using QLS (open symbols). Values for the slopes are in all cases consistent with a random-coil model and not with a rigid sphere or a rod.]...

All of the observations made for random ionomer nonaqueous (polar) solutions parallel those for polyelectrolyte aqueous solutions the difference is only quantity, not the quality. These include upturn in a viscosity curve, negative angular dependence at low concentration and positive dependence at higher concentration in Zimm plots, appearance of two modes in dynamic scattering, and a drop in conductance. 

The crossover between the Kirkwood-Riseman-Zimm behavior and the Rouse behavior requires a better understanding, in terms of the contributing factors for the occurrence of a maximum in the plot of reduced viscosity against polyelectrolyte concentration at low salt concentrations. A firm understanding of the structure factor of polyelectrolyte solutions at concentrations comparable to the overlap concentration is necessary. 

In eq. (5.27) quantities JeR and [ ] are equal to those obtained by Zimm. According to Cerf, the internal friction factor ( ) can be determined by systematically varying solvent viscosity rj0, e.g. by changing the temperature of measurement or the composition of a mixed solvent. In this way, a straight line should be obtained for a plot of tan a vs. rj0. The positive intercept of this line with the ordinate axis should be equal to the second term on the right-hand side of eq. (5.27). An indispensible condition for this procedure is that the intrinsic viscosity [rj] is independent of the solvents used. Otherwise one should plot the product rf rj0 on the abscissa. 

FIG. 9-15. Logarithmic plots of [C ] and [G"] against frequency (unreduced) calculated from Zimm-Kilb theory for star-branched polystyrenes with molecular weight 10 in a solvent with viscosity 0.01 poise at 25 C, with large N and h = 0.25 or 0.05, and different degrees of branching from/= 2 (linear) to/= 13,... 

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