乙基纤维素手性液晶材料的制备与结构色调控

Preparation and Structural Color Regulation of Ethyl Cellulose Chiral Liquid Crystal Materials

  • 摘要: 纤维素基手性液晶结构色材料具有绿色环保、色彩稳定、动态可调等优良特性。本文基于乙基纤维素(EC)的光交联策略,构建了具有多重响应结构色光学特性的EC手性液晶材料,系统探究EC浓度、环境温度及光交联程度对手性液晶材料结构色的调控规律与光学响应特性。研究结果表明:EC凝胶具有鲜艳的结构色和明显的胆甾型液晶双折射特性,随EC浓度升高,液晶凝胶结构色明显蓝移,反射波长从769 nm蓝移至393 nm;随环境温度升高,EC液晶凝胶的颜色由红色调节至蓝色,反射波长从731 nm蓝移至491 nm;随光交联程度的增加,EC液晶材料的结构色呈规律蓝移现象,反射波长从611 nm,蓝移至502 nm;光交联后,左旋圆偏振反射趋于线偏振或无序的散射,结构色稳定为蓝色不再变化。基于EC液晶材料可控光学响应行为,利用光掩模技术可精准制备多重刺激响应的结构色图案,实现了动态的可视化信息加密应用。综上,EC手性液晶材料在高端防伪和光学显示等领域具有良好的应用前景。

     

    Abstract: Cellulose-based chiral liquid crystal structural color materials exhibit excellent properties such as environmental friendliness, color stability, and dynamic tunability. In this study, based on a photocrosslinking strategy of ethyl cellulose (EC), EC chiral liquid crystal materials with multiple responsive structural color optical characteristics were constructed. The regulatory effects of EC concentration, ambient temperature, and the degree of photocrosslinking on the structural color and optical response of the chiral liquid crystal materials were systematically investigated. The results show that EC gels display vivid structural colors and distinct cholesteric liquid crystal birefringence characteristics. As EC concentration increases, the structural color of the liquid crystal gels undergoes a significant blueshift, with the reflection wavelength shifting from 769 nm to 393 nm. With increasing ambient temperature, the color of the EC liquid crystal gels changes from red to blue, and the reflection wavelength shifts from 731 nm to 491 nm. As the degree of photocrosslinking increases, the structural color of the EC liquid crystal materials exhibits a regular blueshift, with the reflection wavelength shifting from 611 nm to 502 nm. After photocrosslinking, the left-handed circularly polarized reflection gradually transforms into either linearly polarized reflection or disordered scattering, and the structural color stabilizes as blue with no further change. Based on the controllable optical response behavior of the EC liquid crystal materials, photomask technology can be used to precisely fabricate multiple stimulus-responsive structural color patterns, enabling dynamic visual information encryption applications. In summary, EC chiral liquid crystal materials hold great promise for applications in advanced anti-counterfeiting and optical displays.

     

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