Nanostructured hafnium-doped strontium oxide film for homeotropic/homogeneous convertible liquid crystal alignment depending on the curing temperature

IF 4.5 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

International Journal of Smart and Nano Materials Pub Date : 2022-08-31 DOI:10.1080/19475411.2022.2116736

Dong Hyun Kim, Dong Wook Lee, J. Oh, Jonghoon Won, Hae‐Chang Jeong, Dae‐Shik Seo

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引用次数: 3

Abstract

ABSTRACT A hafnium strontium oxide (HfSrO) liquid crystal (LC) alignment film was efficiently created through brush coating, and its ability to change the LC alignment direction was confirmed. A brush was applied to HfSrO sol coated on an indium-tin oxide substrate, after which the coating was solidified at various curing temperatures. It was confirmed that a directional micro/nanostructure was formed above 280°C due to the shear stresses caused by the movement of the brush hairs. Surface chemical changes were analyzed by using X-ray photoelectron spectroscopy and contact angle measurements. As the curing temperature increased, the prevalence of oxygen bonds increased and the contact angle decreased, thereby increasing the surface energy. The anisotropic boundary of the microgrooves and the van der Waals forces due to an increase in surface energy changed the alignment direction of LC molecules from vertical to horizontal, as verified through polarized optical microscopy and pretilt angle measurements. Thus, the efficiency of the brush-coating method, which dramatically simplifies the LC alignment film process, was confirmed. The homeotropic/homogeneous LC alignment property of the HfSrO film produced through brush coating depending on the curing temperature provides an innovative approach for LC alignment. GRAPHICAL ABSTRACt

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纳米结构掺铪氧化锶薄膜用于垂直/均匀可转换液晶取向，取决于固化温度

摘要通过刷涂有效地制备了铪锶氧化物（HfSrO）液晶（LC）取向膜，并证实了其改变LC取向方向的能力。将刷子施加到涂覆在铟锡氧化物衬底上的HfSrO溶胶上，之后涂层在各种固化温度下固化。已证实，由于刷毛运动引起的剪切应力，在280°C以上形成了定向微/纳米结构。通过X射线光电子能谱和接触角测量分析了表面化学变化。随着固化温度的升高，氧键的存在率增加，接触角减小，从而增加了表面能。通过偏振光学显微镜和预倾角测量验证，由于表面能的增加，微槽的各向异性边界和范德华力将LC分子的排列方向从垂直变为水平。因此，刷涂法的效率得到了证实，它极大地简化了LC取向膜工艺。通过刷涂制备的HfSrO膜的垂直/均匀LC取向特性取决于固化温度，为LC取向提供了一种创新的方法。图形ABSTRACt

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来源期刊

International Journal of Smart and Nano Materials MATERIALS SCIENCE, MULTIDISCIPLINARY-

CiteScore

6.30

自引率

5.10%

发文量

审稿时长

11 weeks

期刊介绍： The central aim of International Journal of Smart and Nano Materials is to publish original results, critical reviews, technical discussion, and book reviews related to this compelling research field: smart and nano materials, and their applications. The papers published in this journal will provide cutting edge information and instructive research guidance, encouraging more scientists to make their contribution to this dynamic research field.