基于光配向的主链型液晶聚合物预倾角的控制  

Pretilt angle control of main-chain liquid crystal polymer in photoalignment process

作　　者：李川 胡超 房启鹏 刘敏轩 焦玢璋 沈俊[1] 尹韶云[1] LI Chuan;HU Chao;FANG Qipeng;LIU Minxuan;JIAO Binzhang;SHEN Jun;YIN Shaoyun(Chongqing Institute of Green and Intelligent Technology,Chinese Academy of Sciences,Chongqing 400714,China;Chongqing School,University of Chinese Academy Sciences,Chongqing 400714,China)

机构地区：[1]中国科学院重庆绿色智能技术研究院,重庆400714 [2]中国科学院大学重庆学院,重庆400714

出　　处：《液晶与显示》2024年第4期420-426,共7页Chinese Journal of Liquid Crystals and Displays

基　　金：国家自然科学基金(No.62175239)。

摘　　要：液晶的方位角和预倾角的调制广泛应用于各类液晶光子器件的研究。液晶预倾角调控常使用的小分子液晶容易受外场干扰导致液晶预倾角的改变,影响液晶器件稳定性和可靠性。液晶聚合物具有相变温度高、耐热、耐强光、耐机械振动、更加稳定不易受外场干扰等优点,因此液晶聚合物预倾角的可控制备有着重要研究意义。由于液晶单体受液晶与空气界面的锚定能的影响,RM257液晶聚合物的预倾角与液晶层的厚度有关,难以实现预倾角的稳定可控。本研究利用两步法曝光偶氮染料亮黄(BY)薄膜诱导液晶单体RM257倾斜,采用多层旋凃及液晶单体RM257光聚合的方式降低液晶与空气界面锚定能对预倾角的影响,实现RM257主链型液晶聚合物预倾角可控制备。结果表明,采用这一方法制备的液晶聚合物薄膜预倾角可在0°~16°之间连续可调,并具有光热稳定的优点,具备实现液晶光子器件所需的图案化能力。本研究有望为液晶光子与显示器件的制备提供新的材料设计思路。The modulation of azimuth and pretilt angle of liquid crystals(LCs)is widely used in the study of various liquid crystal photonic devices.Comparing to unstability and unreliability of small molecule LC devices fabricated by pretilt angle modulation,LC polymers have some prominent advantages like high phase transition temperature,heating and glaring resistance,stability of mechanical vibration,and so on.Since the LC monomer is affected by the anchoring energy at the interface between LC and air,the pretilt angle of LC polymers is related to the thickness of the LC layer,which makes it difficult to achieve a stable and controllable pretilt angle.In this study,a two-step exposure of azo-dye bright yellow(BY)film was used to guide the tilt of LC monomer RM257,and the effect of the anchoring force at the LC-air interface was reduced by using multilayer spin-coating process and the photopolymerization of LC monomer RM257.Through the controllable preparation of pretilt angle of the LC polymers,it shows that the range of pretilt angle can be continuously adjusted between 0°and 16°with the photo-thermal stability and the potential patterning capability for LC photonic devices.This study is expected to provide a new way for the preparation of LC photonic and display devices.

关 键 词：主链型液晶聚合物 光配向 偶氮材料 预倾角 光热稳定性 

分 类 号：O484.4[理学—固体物理] O753.2[理学—物理]