Morphology of open films of discotic hexagonal columnar liquid crystals as probed by grazing incidence X-ray diffraction.
The structure and the orientation of thermotropic hexagonal columnar liquid crystals are studied by grazing incidence X-ray diffraction (GIXD) for different discotic compounds in the geometry of open supported thin films. Whatever the film deposition mode (either spin-coating or vacuum evaporation) and the film thickness, a degenerate planar alignment with the liquid crystalline columns parallel to the substrate is found. However, if a specific thermal process is applied to the liquid crystal film, homeotropic anchoring (columns normal to the interface) can be stabilized in a metastable state.
Grelet
Eric
E
Centre de Recherche Paul-Pascal, CNRS -Université de Bordeaux, 115 Avenue Schweitzer, 33600, Pessac, France. grelet@crpp-bordeaux.cnrs.fr
Dardel
Sébastien
S
Bock
Harald
H
Goldmann
Michel
M
Lacaze
Emmanuelle
E
Nallet
Frédéric
F
J Phys Chem B. 2007 Sep 27;111(38):11157-61
17760436
Chem Rev. 2007 Mar;107(3):718-47
17291049
Angew Chem Int Ed Engl. 2006 Mar 3;45(11):1783-6
16470619
Science. 2001 Aug 10;293(5532):1119-22
11498585
J Am Chem Soc. 2005 Aug 17;127(32):11288-93
16089457
Science. 1993 Apr 16;260(5106):323-6
17838247
J Am Chem Soc. 2008 Sep 10;130(36):11953-8
18707182
Angew Chem Int Ed Engl. 2007;46(26):4832-87
17568461
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Oct;78(4 Pt 1):041707
18999445
Chem Soc Rev. 2007 Dec;36(12):1902-29
17982517
Langmuir. 2008 Nov 18;24(22):12742-4
18925759