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Abstract：
Chiral nematic materials have been attracting attention in fields of advanced functional applications due to their unique iridescent colors and tunable helical structure. A precisely decreased pitch is of importance for construction and applications of chiral nematic materials; however, it remains a huge challenge. Herein, cellulose nanocrystal (CNC) is selected as a constructed matrix for chiral nematic films, and ferric chloride (FeCl3) is used as a modification agent. We investigate the effects of the ferric ion loads on the helical structure and optical characteristics of iridescent film. Subsequently, the influence of ferric ions on the assembly process of CNC liquid crystal and the regulation of the structure color of self-assembled monolayers are discussed. Therefore, the CNC/FeCl3 chiral nematic films showed a blueshifted structural color from orange to blue, which highlights a simple route to achieve the regulation of decreased pitch. Further, we have applied this CNC/FeCl3 chiral nematic film for benzene gas detection. The sensing performance shows that the CNC/FeCl3 chiral nematic film reacts to benzene gas, which can be merged into the nematic layer of the CNC and trigger the iron ions chelated on the CNC, consequently arousing the redshift of the reflected wavelength and the effective colorimetric transition. This CNC/FeCl3 chiral nematic film is anticipated to boost a new gas sensing mechanism for faster and more effective in-situ qualitative investigations.
摘要：
手性向列型材料由于其独特的虹彩颜色和可调的螺旋结构而在高级功能应用领域受到关注。精确降低螺距对于手性向列材料的构造和应用至关重要；然而，这仍然是一个巨大的挑战。在这里，选择纤维素纳米晶体（CNC）作为手性向列型薄膜的构建基质，和氯化铁(FeCl3)用作改性剂。我们研究了铁离子负载对虹彩薄膜螺旋结构和光学特性的影响。随后，讨论了三价铁离子对CNC液晶组装过程的影响以及自组装单层结构颜色的调节。因此,CNC/FeCl3手性向列型薄膜显示从橙色到蓝色的蓝移结构颜色，这突出了一条简单的路线来实现降低音高的调节。Further,我们已经将这种CNC/FeCl3手性向列型薄膜用于苯气体检测。传感性能表明，CNC/FeCl3手性向列型薄膜与苯气体反应，可以合并到CNC的向列层中，并触发CNC上螯合的铁离子，因此引起反射波长的红移和有效的比色转变。这种CNC/FeCl3手性向列型薄膜有望促进一种新的气体传感机制，以实现更快，更有效的原位定性研究。
