Abstract
We investigate the mesomorphic properties of main-chain chiral-smectic elastomers cross-linked in different phases, analyzing three samples prepared by photo-cross-linking a chiral smectic C (SmC^*) polymer in the SmC^*, SmA, and isotropic (Iso) phases. The SmC^*-cross-linked elastomer exhibits successive SmC^*-SmA-Iso transformations similarly to the precursor polymer. However, only the orthogonal molecular alignment due to the SmA structure appears in the SmA-cross-linked elastomer. Moreover, isotropic alignment remains in most of the Iso-cross-linked elastomer even at room temperature. Since the effect of the fixed orientation is not localized in the vicinity of cross-links because of the direct coupling between the mesogenic orientation and the polymeric conformation in main-chain smectic elastomers, the transformation from the cross-linked phase to a higher-order phase might be forbidden.
