Wang Shuaiqi, Lin Bingqun, Zeng Yihan, Pan Mingzhu
College of Materials Science and Engineering, Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China.
Polymers (Basel). 2024 Jan 31;16(3):399. doi: 10.3390/polym16030399.
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 (FeCl) 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/FeCl 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/FeCl chiral nematic film for benzene gas detection. The sensing performance shows that the CNC/FeCl 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/FeCl chiral nematic film is anticipated to boost a new gas sensing mechanism for faster and more effective in-situ qualitative investigations.
手性向列相材料因其独特的彩虹色和可调谐的螺旋结构，在先进功能应用领域备受关注。精确降低螺距对于手性向列相材料的构建和应用至关重要；然而，这仍然是一个巨大的挑战。在此，选择纤维素纳米晶体（CNC）作为手性向列相薄膜的构建基质，并使用氯化铁（FeCl）作为改性剂。我们研究了铁离子负载量对彩虹色薄膜螺旋结构和光学特性的影响。随后，讨论了铁离子对CNC液晶组装过程的影响以及对自组装单分子层结构颜色的调控。因此，CNC/FeCl手性向列相薄膜呈现出从橙色到蓝色的蓝移结构色，这突出了一种实现螺距降低调控的简单途径。此外，我们已将这种CNC/FeCl手性向列相薄膜应用于苯气体检测。传感性能表明，CNC/FeCl手性向列相薄膜对苯气体有反应，苯可融入CNC的向列相中并触发螯合在CNC上的铁离子，从而引起反射波长的红移和有效的比色转变。这种CNC/FeCl手性向列相薄膜有望推动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。
