Abstract
The elastic properties of the solid state of linear oligomers are closely related to their special intra-and inter-molecular interactions. This is proved for the perfluoroalkanes C16F34 and C20F42. The elastic tensors of both materials have been measured with Brillouin spectroscopy as a function of temperature. Both systmes show an extremely weak shear stiffnessc 44, indicating the existence of a smectic-B like structure and an unexpected strong elastic anisotropy inversion in the premelting phase. Moreover a Curie-Weiss-law behavior was found for the stiffness constantc 33 indicating the existence of a soft longitudinal acoustic phonon mode. The transition temperatureT c is for C20F42 below the melting point. The elastic properties are purely static. The observations are tentatively attributed to an intermolecular premelting process.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Strobl, G.R., Eckel, R.: J. Polym. Sci.14, 913 (1976)
Sakurada, I., Ito, T., Nakamae, K.: J. Polym. Sci. C15, 75 (1966)
Strobl, G.R.: Colloid Polym. Sci.254, 170 (1976)
Pechold, W., Dollhopf, W., Engel, E.: Acoustica17, 62 (1966)
Heyer, D., Buchenau, U., Stamm, M.: J. Polym. Sci.22, 1515 (1984)
Buchenau, U.: Solid State Commun.32, 1329 (1979)
Krüger, J.K., Bastian, H., Asbach, G.I., Pietralla, M.: Polym. Bull.3, 633 (1980)
Krüger, J.K., Pietralla, M., Unruh, H.-G.: Phys. Status Solidi (a)71, 493 (1982)
Krüger, J.K., Pietralla, M., Unruh, H.-G.: Colloid Polymer Sci.261, 409 (1983)
Krüger, J., Peetz, L., Pietralla, M.: Polymer19, 1397 (1978)
Krüger, J.K., Marx, A., Peetz, L., Roberts, R., Unruh, H.-G.: Colloid Polym. Sci.264, 403 (1986)
Wunderlich, B., Grebowics, J.: Adv. Polym. Sci.60/61, 1 (1984)
Starkweather, H.W.: Macromolecules19, 1131 (1986)
Schwickert, H.: Dissertation, Mainz 1984
IRE Proc. Stand. Piezoelectric Crystals37, 1378 (1949)
Krüger, J.K., Peetz, L., Unruh, H.-G., Eich, M., hermann-Schönherr, Wendorff, J.H.: Phys. Rev. A37, 2637 (1988)
Rabolt, J.F., Fanconi, B.: Polymer18, 1258 (1977)
Schaufele, R.F., Shimanouchi, T.: J. Chem. Phys.47, 3605 (1967)
Piseri, L., Powell, B.M., Dolling, G.: J. Chem. Phys.58, 158 (1973)
Rehwald, W.: Adv. Phys.22, 721 (1973)
Höhne, G.W.: Private communication
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Marx, A., Krüger, J.K. & Unruh, H.G. Elastic properties of the premelting phases of the perfluoroalkanes C16F34 and C20F42 . Z. Physik B - Condensed Matter 75, 101–107 (1989). https://doi.org/10.1007/BF01313572
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01313572