Planar Alignment of Columnar Discotic Liquid Crystals by Isotropic Phase Dewetting on Chemically Patterned Surfaces
Planar Alignment of Columnar Discotic Liquid Crystals by Isotropic Phase Dewetting on Chemically Patterned Surfaces
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DOI：
10.1002/adfm.200902140
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发表时间：
2010-03-24
影响因子：
19
通讯作者：
Evans, Stephen D.
中科院分区：
文献类型：
--
作者：
Bramble, Jonathan P.;Tate, Daniel J.;Evans, Stephen D.
提出了一种在表面上形成平面排列的柱状分散液晶（cDLC）的新方法，该方法还可以控制方位角。通过在金上微接触印刷有机硫醇自组装单层（SAM）或通过在硅上深紫外图案化有机硅烷SAM，表面被化学图案化为条纹。然后，这些用于通过在各向同性相中去湿来分离cDLC的长液滴。在从各向同性冷却到六方柱状相时，偏光显微镜显示cDLC以平面取向排列。给出了三种苯并菲衍生物（HAT-6; HHTT，H7 T）和一种酞菁衍生物（8H（2）Pc）的结果。发现H7 T和HAT-6与垂直于条纹方向的指向矢对齐，而HHTT和8H（2）Pc与条纹方向平行对齐。这种用于产生DLC的平面对准的柱状相的相对简单的新方法提供了对方位角的控制：cDLC的有机场效应晶体管应用所需的条件。
A novel method of creating planar aligned columnar discotic liquid crystals (cDLCs) on surfaces, which also gives control over the azimuthal angle, is presented. Surfaces are chemically patterned with stripes via microcontact printing of organothiol self-assembled monolayers (SAMs) on gold, or via deep UV patterning of organosilane SAMs on silicon. These are then used to isolate long droplets of cDLCs by dewetting in the isotropic phase. Upon cooling from the isotropic into the hexagonal columnar phase, polarizing microscopy reveals that the cDLC aligns in a planar orientation. Results for three triphenylene derivatives (HAT-6; HHTT, H7T) and for a phthalocyanine derivative (8H(2)Pc) are presented. H7T and HAT-6 are found to align with the director perpendicular to the stripe direction, but HHTT and 8H(2)Pc align parallel to the stripe direction. This relatively simple new method for creating planar aligned columnar phases of DLCs gives control over the azimuthal angle: a condition required for organic field-effect transistor applications of cDLCs.