Die Winkelverteilung der kritischen Opaleszenz und die Messung molekularer Wechselwirkung

Debye, Von P.

doi:10.1002/macp.1960.020350114

Cited by 9 publications

(2 citation statements)

References 9 publications

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“…Among the topics that will not be discussed here, the critical opalescence studies on binary liquid mixtures and polymer solutions have been reviewed repeatedly (103)(104)(105)(106). The same is valid for the investigations of scattering by polymer solids and films (451,452,454).…”

Section: Theoretical Developmentsmentioning

confidence: 99%

“…The advances made in the theory of light scattering will be surveyed following the usual classification according to the shape and intrinsic properties of scattering objects. Among the topics that will not be discussed here, the critical opalescence studies on binary liquid mixtures and polymer solutions have been reviewed repeatedly (103)(104)(105)(106). The same is valid for the investigations of scattering by polymer solids and films (451,452,454)• Spherical Particles.…”

Section: Developmentsmentioning

confidence: 99%

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Light Scattering

Kratohvil¹

1964

Anal. Chem.

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Section: Theoretical Developmentsmentioning

confidence: 99%

Section: Developmentsmentioning

confidence: 99%

Light Scattering

Kratohvil¹

1964

Anal. Chem.

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Thermodynamic parameters of polymer‐solvent systems from light‐scattering measurements below the theta temperature

Scholte

1971

J. Polym. Sci. A‐2 Polym. Phys.

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As is well known, the chemical potentials of polymer and solvent in solution and, hence, the Flory‐Huggins interaction parameter χ can be determined from scattered light intensities from dilute and concentrated solutions of the polymer in the solvent concerned. Preferably, measurements should be performed at temperatures as low as possible, provided the temperature exceeds the cloudpoint for the concentration used. It is shown that the lower the temperature and, consequently the higher the scattered light intensity, the better is the accuracy of the parameters obtained. At each temperature the scattered light intensity shows a maximum at some concentration. Below the theta temperature the ratio of scattered light intensity and concentrations also shows a maximum at some concentration. The values and the concentrations of these maxima for various temperatures enable the maximum of the spinodal to be determined. The spinodal itself can be determined by an extrapolation procedure of the reciprocal scattered light intensities. Measurements have been performed with three narrow‐distribution polystyrene samples in cyclohexane. On the basis of the results, χ, and its dependence on concentration, temperature, and molecular weight can be determined to high accuracy.

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Optic, thermodynamic, and rheologic properties of concentrated solutions of polystyrene and polyisobutylene

Tager¹,

Andreeva²

1967

J. polym. sci., C Polym. symp.

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The light scattering by moderately concentrated solutions of polystyrene and poly‐isobutylene has been studied. The dependence of excess light scattering on the concentration of the solution has been expressed by a curve with a maximum, the height and sharpness of which depend on the temperature, the molecular weight of the polymer, and on its interaction with the solvent. With an increase in the molecular weight of the polymer the position of the maximum is displaced toward lower volume fraction φ2, which with impairment of the thermodynamic interaction the maximum is found at higher φ2. The position of the maximum does not depend on the temperature. Light scattering increases with a drop in temperature if the system has an upper critical solution temperature (UCST) and with a rise in temperature if phase separation takes place when the solution is heated (LCST). These results are in accord with the signs of the excess thermodynamic functions in these systems. Comparing the results with the Newtonian viscosity data on the same systems and with the literature on the aggregation of macromolecules, we conclude that polymer solutions exhibit two regions at concentration below φ2 = 0.5 characterized by differences in: (1) the region of interaction of uncoiling macromolecules, which is characterized by a considerable increase in light scattering and a relatively slight increase in viscosity; and (2) the region where the aggregates form a continuous random network, the order of which increases with the increase of concentration. This is followed by a decrease in fluctuations of concentration and hence of light scattering and a sharp increase in viscosity.

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Die Winkelverteilung der kritischen Opaleszenz und die Messung molekularer Wechselwirkung

Cited by 9 publications

References 9 publications

Light Scattering

Light Scattering

Thermodynamic parameters of polymer‐solvent systems from light‐scattering measurements below the theta temperature

Optic, thermodynamic, and rheologic properties of concentrated solutions of polystyrene and polyisobutylene

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