Patterned alignment of liquid crystals on selectively thiol-functionalized photo-orientation layers

A method for the alignment of liq. crystals is presented allowing to control the azimuthal and polar anchoring directions. Selectively deposited thiols are used which are covalently linked to photoalignment layers. First, uncured linearly photopolarizable (LPP) derivs. (Staralign 2110 CP2) were spin-coated on glass substrates covered with a transparent layer of ITO. The uncured LPP material was treated with UV irradn. using an illumination mask. Then, the partially cured LPP material was covered with the thiol (n-decanethiol, n-hexadecanethiol, or 6-mercapto-1-hexanol) contg. 1 wt.% of a thermal radical initiator. The reaction mechanism of the thermally initiated thiol/ene free-radical addn. reaction is described. The samples were characterized by IR spectroscopy. Display cells were constructed by pairing 2 substrates and fixing them with an UV-curable acrylate-based adhesive. They were filled with the liq. crystal via capillary motion at elevated temps. above the clearing point of the mesogen. The alignment process was evaluated by polarized optical microscopy. The alignment process of the liq. crystals is described in detail, and possible applications are discussed concerning liq.-crystal-based devices. [on SciFinder (R)