par Gearba, Raluca Raluca R.I.;Anokhin, Denis 
;Bandar, Alexander A.I.;Bras, Wim;Jahr, Michael;Lehmann, Matthias ;Ivanov, Dimitri
Référence Advanced materials, 19, 6, page (815-820)
Publication Publié, 2007-03
;Bandar, Alexander A.I.;Bras, Wim;Jahr, Michael;Lehmann, Matthias ;Ivanov, Dimitri Référence Advanced materials, 19, 6, page (815-820)
Publication Publié, 2007-03
Article révisé par les pairs
| Résumé : | The formation of macroscopic homeotropically aligned open film of columnar liquid crystal (LC) monodomain on nanopatterned surfaces fabricated by means of friction transfer of poly(tetrafluorethylene), PTFE, was discussed. Supported LC films were prepared by solution-casting or spin-coating. The columnar alignment in the films was studied as a function of temperature by polarized optical microscopy (POM) and synchrotron X-ray diffraction (XRD) in transmission geometry. The schematic chemical structures of the molecules, during heating underwent a transition from a columnar rectangular (Colr) to a columnar hexagonal mesophase (Colh) at 49°C followed by isotropization at 166°C. The Colh phase is metastable, or monotropic, and converts into a stable crystalline columnar phase (Cr) after several hours of annealing at room temperature. |
