Viscosities of dilute solutions were measured for four generations of peripherically charged dendronized poly(methyl methacrylate)s (CDPs) of two different chain lengths in water (no salt added) and of their uncharged analogues (UCPs) in chloroform. In all cases it was possible to describe ln(ηsolution/ηsolvent) as a function of polymer concentration by two adjustable parameters: a hydrodynamic interaction parameter B and [η], the intrinsic viscosity of the polymer. The [η] values for the first generation of polyelectrolytes are markedly lower (given number of monomeric units) than that of aqueous solutions of Na-polystyrene sulfonate reported earlier, despite the fact that each monomeric unit is much larger and bears two charges instead of one; as the number of generation rises, [η] falls markedly for the CDPs as well as for the UCPs, where the effect is considerably more pronounced for the polyelectrolyte. The increase in molar mass M associated with the addition of dendrons leads to a maximum in the molar hydrodynamic volume [η]M for the second generation of the CDP; in case of the UCPs this volume increases steadily. The interaction parameter B is normally positive but may for the higher generations become negative, corresponding to a more than exponential augmentation of η with polymer concentration. A consistent description of the findings is presented in terms of intra- and intermolecular interactions between the -NH and -O- groups of the dendrons and the distances of the charges from the polymer backbone.

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The activities of methanol, ethanol, 2-propanol, and 1-butanol in poly(propylene glycol) (PPG) (M p:  1000) solutions have been measured by the isopiestic method at 25 °C. Sodium iodide and calcium chloride were used as the isopiestic standards for the calculation of activities. The original equation of Flory−Huggins and the modified Flory−Huggins equation with concentration dependent interaction parameters have been used for the correlation of obtained experimental solvent activity data. Better agreement with the experimental data was obtained using the modified Flory−Huggins equation.

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The activities of methanol, ethanol, 2-propanol, and 1-butanol in poly(vinylpyrolidone) (PVP) (weightaverage relative molar mass, M w ) 10 000) solutions have been measured by the isopiestic method at 25 °C. Sodium iodide and calcium chloride were used as the isopiestic standards for the calculation of activities. A polynomial equation, the original Flory-Huggins equation, and the modified Flory-Huggins equation with concentration-dependent interaction parameters have been used for the correlation of the experimental solvent activity data. The strength of interaction between different alcohols and the polymer was discussed on the basis of the obtained Flory-Huggins interaction parameters.

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Flory‐Huggins interaction parameters were determined as a function of composition for solutions of linear and of branched polyisoprene in cyclohexane (CH) at 25, 45, and 65 °C by means of vapor pressure measurements (moderate to concentrated solutions) and by vapor pressure osmometry (dilute solutions). The results demonstrate that CH is a considerably worse solvent for branched polyisoprene than for the linear analog at all temperatures and at all compositions. This observation corroborates the expectation based on a recent phenomenological approach, which accounts explicitly for the incapability of the segments of an individual polymer molecule to spread out over the entire volume of the system and for its ability to adjust its chain conformation to an altering molecular environment.magnified image