Molecular and Nanoscale Physics, School of Physics and Astronomy, Centre for Molecular Nanoscience (CMNS), and Institute of Microwaves and Photonics, University of Leeds, Leeds LS2 9JT, United Kingdom.
ACS Appl Mater Interfaces. 2010 Dec;2(12):3686-92. doi: 10.1021/am100832p. Epub 2010 Nov 11.
We report on the development of novel cyano-biphenyl-based thiolate self-assembled monolayers designed to promote homeotropic alignment of calamitic liquid crystals. The molecules developed contain an ortho-nitrobenzyl protected carboxylic acid group that on irradiation by soft UV (365 nm) is cleaved to yield carboxylic acid groups exposed at the surface that promote planar alignment. Using a combination of wetting, X-ray photoelectron spectroscopy, Fourier transform-infrared reflection absorption spectroscopy, and ellipsometry we show that high photolysis yields (>90%) can be achieved and that the patterned SAMs are suitable for the controlled alignment of calamitic liquid crystals. This study further shows that such photo-patterned SAMs can be used to control the formation of focal conic domains (FCDs) in the smectic-A phase in terms of positioning and size confinement on surfaces.
我们报告了新型氰基联苯硫醇自组装单分子层的开发，旨在促进向列液晶的垂直排列。所开发的分子含有邻硝基苄基保护的羧酸基团，该基团在软 UV（365nm）照射下被切断，生成暴露在表面的羧酸基团，从而促进平面排列。通过润湿、X 射线光电子能谱、傅里叶变换红外反射吸收光谱和椭圆偏振法的组合，我们表明可以实现高光解产率（>90%），并且图案化的 SAM 适合向列液晶的可控排列。这项研究进一步表明，这种光图案化的 SAM 可用于控制在表面上的定位和尺寸限制方面，在近晶 A 相中的焦锥畴（FCD）的形成。
