J. Phys. II France
Volume 4, Numéro 10, October 1994
Page(s) 1813 - 1822
DOI: 10.1051/jp2:1994234
J. Phys. II France 4 (1994) 1813-1822

Optical studies of supramolecular tubular structures generated by taper-shaped side groups in the columnar hexagonal phase

Jian-Feng Li1, James A. Heck2, Virgil Percec2, Charles Rosenblatt1, 2, Joseph S. Collura3 and Michael R. Fisch3

1  Departement of Physics, Case Western Reserve University, Cleveland, Ohio 44106, U.S.A.
2  Macromolecular Science, Case Western Reserve University, Cleveland, Ohio 44106, U.S.A.
3  Departement of Physics, John Caroll University, University Heights, Ohio 44118, U.S.A.

(Received 2 May 1994, received in final form 6 June 1994, accepted 23 June 1994)

Birefringence measurements in the columnar hexagonal phase ( $\Phi_{\rm h}$) and turbidity measurements in the high temperature isotropic phase (I) have been performed on a polymethacrylate (12-AG-4EO-PMA) having taper-shaped side groups ; the same measurements were also performed on a self-assembling monomeric precursor (12-AG-4EO-OH). We found that the optical retardation increases strongly with decreasing temperature in the $\Phi_{\rm h}$ phase, whereas the turbidity shows no systematic pretransitional behavior on approaching the $\Phi_{\rm h}$-I phase transition temperature $T_{\Phi_{\rm h}-{\rm I}}$ from above. Additionally, we found a large bisphasic region around $T_{\Phi_{\rm h}-{\rm I}}$ for mixtures of the monomer and polymer. These results are discussed in terms of the turbidity being dominated by columnar, rather than orientational, fluctuations.

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