Huggins coefficient

The Huggins coefficient kn is of order unity for neutral chains and for polyelectrolyte chains at high salt concentrations. In low salt concentrations, the value of kn is expected to be an order of magnitude larger, due to the strong Coulomb repulsion between two polyelectrolyte chains, as seen in the case of colloidal solutions of charged spheres. While it is in principle possible to calculate the leading virial coefficients in Eq. (332) for different salt concentrations, the essential feature of the concentration dependence of t can be approximated by... 

Gundert F, Wolf BA (1986) Viscosity of dilute polymer solutions molecular weight dependence of the Huggins coefficient Makromol Chem 187 2969... 

Here kH is the Huggins coefficient. The intrinsic viscosity decreases and the Huggins coefficient increases, as micelles become smaller. On micellization, ijsp/c has been observed to increase for some systems but to decrease for others, and unfortunately there are no firm rules governing which case will prevail for a given block copolymer solution. The viscosities of polymer solutions are measured in capillary flow viscometers, which are described in detail by Macosko (1994). 

Abbreviations A H Huggins coefficient M, molar mass R, radius of gyration RD, core radius p, association number AmcH°, standard enthalpy of micellization, AmlcG°, standard Gibbs energy of micellization A2, second virial coefficient. Ru, hydrodynamic radius. 

Fig. 3.29 Dependence of (a) apparent molecular weight, (b) sedimentation coefficient and (c) intrinsic viscosity fi/, and Huggins coefficient, ktl. on solvent composition (methanol-water-0.1 M LiBr mixtures) for solutions of a PS-poly(4-vinyl-A -ethylpyri-dinium bromide) = 32.7kgmol l, 8% PS) diblock (Selb and Gallot 1981a).

Here, the intrinsic viscosity [r ] is defined as the infinite dilution limit of the reduced viscosity and kH is Huggins coefficient. This result is valid up to the second order in concentration. The PFPE solvent interaction is related to kfj [r ]2. For flexible polymer chains in a theta solvent, kn has been found to vary from 0.4 to 1.0 [110]. From the intercept and slope, we obtain [r ] and kH. These values... 

Freed KF, Edwards SF (1975) Huggins coefficient for the viscosity of polymer solutions. J Chem Phys 62(10) 4032-4035... 

The term that is linear in concentration contains the intrinsic viscosity [r]] and the quadratic term includes the Huggins coefficient h, which plays the role of the second virial coefficient for viscosity. Intrinsic viscosity [rj is the initial slope of a plot of relative viscosity r]/r]s against concentration. Since... 

Table 1.4 Representative Mark-Houwink and Huggins coefficients of linear polymers...

Determination of the intrinsic viscosity for three different polybutadiene samples in tetrahydrofuran at 25°C. Each sample exhibits linear Huggins (filled symbols) and Kraemer (open symbols) plots that extrapolate to the intrinsic viscosity at zero concentration. All three polymers have Huggins coefficients of 0.37. 

Figure 1.24 shows experimental determinations of the intrinsic viscosity. When both the Huggins and Kraemer equations provide the same intrinsic viscosity and Huggins coefficient, the higher-order terms in these equations can be safely ignored. On the other hand, if the Huggins and Kraemer plots are curved and do not give the same intercept, viscosity measurements need... 

The relationship between observed viscosity and intrinsic viscosity depends on the volume occupied by the polymer chains (dependent on the first power of their concentration) and the interactions between polymer chains (in the dilute and semi-dilute regions, dependent on the second power of their concentration). The resulting equation, eqn. (4.17), is known as the Huggins equation, with kii being the (dimensionless) Huggins coefficient, which measures chain-chain interaction ... 

Viscometry measurements were also conducted. The Huggins coefficients increase with increasing molecular weight for the amine-capped polymers. This behavior is consisted with a star-like structure. For the zwitterionic samples constant kn values, around 1.1 were obtained, meaning that rather compact structures exist in solution. 

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