Abstract
Light scattering and sedimentation equilibrium measurements were made on concentrated solutions of a rodlike polysaccharide schizophyllan using three samples of different molecular weights. The data were analyzed to obtain the partial derivative [∂Δμ0/∂φ]Mn of the excess chemical potential of the solvent with respect to the polymer volume fraction φ. The results for isotropic solutions were analyzed by the theory of Flory and Abe for rodlike polymers, yielding a non-vanishing interaction parameter χ. For any of the samples investigated, χ was negative and decreased with increasing φ. No appreciable dependence of χ on molecular weight was found. Sedimentation measurement was also made on biphasic mixtures consisting of isotropic and cholesteric phases at equilibrium to evaluate [∂Δμ0/∂φ]Mn at the phase boundary in the two phases. No theory was found to describe precisely our experimental data.
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L. Onsager, Ann. N. Y. Acad. Sci., 51, 627 (1947).
A. Ishihara, J. Chem. Phys., 19, 1142 (1951).
P. J. Flory, Proc. R. Soc., London, Ser. A, 234, 73 (1956).
M. A. Cotter, Phys. Rev. A., 10, 629 (1974).
K. Kubo and K. Ogino, Mol. Cryst. Liq. Cryst., 53, 207 (1979).
K. Kubo, Mol. Cryst. Liq. Cryst., 74, 71 (1981).
T. Norisuye, T. Yanaki, and H. Fujita, J. Polym. Sci., Polym. Phys. Ed., 18, 547 (1980).
T. Yanaki, T. Norisuye, and H. Fujita, Macromolecules, 13, 1462 (1980).
K. Van, T. Norisuye, and A. Teramoto, Mol. Cryst. Liq. Cryst., 78, 123 (1981).
K. Van and A. Teramoto, Polym. J., 14, 999 (1982).
T. Itou, K. Van, and A. Teramoto, J. Appl. Polym. Sci., in press.
B. H. Zimm, J. Chem. Phys., 14, 164 (1946).
Th. G. Scholte, J. Polym. Sci., A-2, 8, 841 (1970).
Th. G. Scholte, Eur. Polym. J., 6, 1063 (1970).
Z X (X= LS, SED) refers to a given amount of the solvent. Therefore, M0 is the molecular weight of the “equivalent solvent” corresponding to this amount and does not necessarily equal that of water.
Y. Kashiwagi, T. Norisuye, and H. Fujita, Macromolecules, 14, 1220 (1981).
P. J. Flory and A. Abe, Macromolecules, 11, 1119 (1978).
This value of M w/M n was obtained from the observed M z/M w by assuming that the molecular weight distribution of each sample was of the Schulz type.
G. Lasher, J. Chem. Phys., 53, 4141 (1970).
J. P. Straley, Mol. Cryst. Liq. Cryst., 22, 333 (1973).
M. A. Cotter, J. Chem. Phys., 66, 1098 (1977).
H. Reiss, H. L. Frisch, and J. L. Lebowitz, J. Chem. Phys., 31, 369 (1959).
It can be shown on the basis of the Onsager theory that for a polydisperse sample, the light scattering and sedimentation equilibrium second virial coefficients are related to M w, whereas the osmotic one to M n. However, there is no method for evaluating the polydispersity effect on [∂Δμ0/∂φ]X (X= LS, SED) at high concentration. Thus, it is a reasonable first approximation to use the same type of average for Vp and x in eq 18 to compute theoretical values of Δμ0.
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Van, K., Teramoto, A. Light Scattering and Sedimentation Equilibrium Study on Concentrated Solutions of a Rodlike Polysaccharide Schizophyllan. Polym J 17, 409–419 (1985). https://doi.org/10.1295/polymj.17.409
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DOI: https://doi.org/10.1295/polymj.17.409