title: Effect of interfaces on the alignment of a discotic liquid-crystalline phthalocyanine.
abstract: This paper deals with the influence of the nature and number of solid interfaces on the alignment of the columns in a semiconducting discotic liquid crystal. The solid substrates have been characterized in terms of their roughness and surface energy. The alignment of the discotic liquid crystal columns on these substrates has been determined by optical microscopy under crossed polarizers and by tapping-mode atomic force microscopy. The nature of the substrates has negligible influence on the alignment. The key parameter is the confinement imposed to the film. These surprising observations are explained by the antagonist alignment role of gas and solid interfaces.
authors.affiliation: Laboratory of Polymer Chemistry, CP 206/1, Université Libre de Bruxelles, Boulevard du Triomphe, 1050 Bruxelles, Belgium.
authors.forename: Vinciane
authors.initials: V
authors.lastname: De Cupere
authors.forename: Julien
authors.initials: J
authors.lastname: Tant
authors.forename: Pascal
authors.initials: P
authors.lastname: Viville
authors.forename: Roberto
authors.initials: R
authors.lastname: Lazzaroni
authors.forename: Wojciech
authors.initials: W
authors.lastname: Osikowicz
authors.forename: William R
authors.initials: WR
authors.lastname: Salaneck
authors.forename: Yves Henri
authors.initials: YH
authors.lastname: Geerts