Self-assembling Structures and Sol-Gel Transition of Optically Active and Racemic 12-Hydroxystearic Acids in Organic Solvents

  • Hiroyuki TakenoEmail author
  • Tomomitsu Mochizuki
  • Kazuto Yoshiba
  • Shingo Kondo
  • Toshiaki Dobashi
Part of the Progress in Colloid and Polymer Science book series (PROGCOLLOID, volume 136)


Self-assembling structures and sol-gel transition in solution of optically active and racemic 12-Hydroxystearic acids (HSA) have been investigated by means of small-angle X-ray scattering (SAXS), differential scanning calorimetry and rheological measurements. Apparently two kinds of gel, transparent gel and turbid gel were obtained in different solvents or by changing concentrations in the same solvent. The melting temperature of the turbid gel is higher than that of the transparent gel. The difference can be qualitatively explained by the dissolution of the crystals (melting point depression) in non-ideal solutions. The SAXS profiles of the transparent gel composed of fibrillar structures have a similar shape at different concentrations, although the intensity is larger for the gels with higher concentrations of 12-HSA. The SAXS analysis reveals that the cross-section of fibrils have square or circular shape (no anisotropic shape) with the radius of gyration 83 Å. On the other hand, for the turbid gel structural inhomnogeneity becomes significant with concentration. The gelation properties and the structures are found to be similar in the racemic HSA gel and the optically active (D-HSA) gel.


Self-assembling structures Sol-gel transition Low-molecular weight gelator Small-angle X-ray scattering 



H. T. acknowledges Prof. T. Hashimoto for his valuable comments.

References and Notes

  1. 1.
    Terech P, Weiss RG (1997) Chem. Rev. 97:3133CrossRefGoogle Scholar
  2. 2.
    Tachibana T, Kambara H (1969) Bull. Chem. Soc. Jpn, 42:3422CrossRefGoogle Scholar
  3. 3.
    Tachibana T, Kambara H (1968) J. Colloid Sci., 28:173CrossRefGoogle Scholar
  4. 4.
    Takahashi A, Nakamura T, Kagawa I (1972) Polymer J. 3:207CrossRefGoogle Scholar
  5. 5.
    Eldridge JE, Ferry JD (1954) J. Chem. Phys. 58:992CrossRefGoogle Scholar
  6. 6.
    Doty P, Wagner H, Singer S, (1947) J. Phys. Chem. 51:32CrossRefGoogle Scholar
  7. 7.
    Newman S, Krigbaum WR, Carpenter KK (1956) J. Phys. Chem. 58:968Google Scholar
  8. 8.
    Hildebrand JH, Scott RL (1950): The solubility of Nonelectrolytes 3rd ed Dover Publications, New YorkGoogle Scholar
  9. 9.
    Flory PJ (1941) J Chem Phys, 9:660CrossRefGoogle Scholar
  10. 10.
    Huggins ML (1941) J Chem Phys, 9:440CrossRefGoogle Scholar
  11. 11.
    In order to experimentally estimate the effect of dispersion of the crystals, we measured the melting temperature of the sample prepared by freeze-drying of 7wt% D,L-12-HSA gel in benzene, i.e., the structures are expected to be frozen in the dispersed state. As a consequence, the melting temperature was 79.4 °C, which is by 1.2 °C lower than that of the bulk crystal. Therefore, the effect of the dispersion of the crystal in the gel state is expected to be smallGoogle Scholar
  12. 12.
    Polymer HandBook, third edGoogle Scholar
  13. 13.
    Van Kreveren (1972): Properties of Polymers, Elsevier Publishing Company, AmsterdamGoogle Scholar
  14. 14.
    Tachibana T, Mori T, Hori K (1980) Bull. Chem. Soc. Jpn, 54:1714CrossRefGoogle Scholar
  15. 15.
    Terech P (1991) Colloid Polym. Sci., 269: 490CrossRefGoogle Scholar
  16. 16.
    Terech P, Rodriguez V, Barnes JD, McKenna GB (1994) Langmuir, 10:3406CrossRefGoogle Scholar
  17. 17.
    Terech P, Pasquier D, Bordas V, Rossat C (2000) Langmuir, 16:4485CrossRefGoogle Scholar
  18. 18.
    Feigin LA, Svergun DI (1987): Structure Analysis by Small-Angle X-ray and Neutron Scattering. Plenum Press, New YorkCrossRefGoogle Scholar
  19. 19.
    Mittelbach, Porod G (1961) Acta Phys Austriaca, 14:185Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Hiroyuki Takeno
    • 1
    Email author
  • Tomomitsu Mochizuki
  • Kazuto Yoshiba
  • Shingo Kondo
  • Toshiaki Dobashi
  1. 1.Department of Chemistry and Chemical Biology, Faculty of EngineeringGunma UniversityKiryuJapan

Personalised recommendations