Zhu Yuchen, Balcerowski Tadeusz, Dumanli Ahu Gümrah
Department of Materials, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.
Henry Royce Institute, The University of Manchester, Oxford Rd, Manchester, M13 9PL, UK.
Small Methods. 2025 Jul;9(7):e2401966. doi: 10.1002/smtd.202401966. Epub 2025 May 19.
Cellulose nanocrystals (CNCs) can spontaneously self-assemble into cholesteric photonic films with vibrant colors with multidomain structures and variations in cholesteric pitch. Herein, an angular deposition technique is employed to harness capillary and Marangoni flows to fabricate CNC photonic films with spatially tunable structural colors spanning from red to blue. A crucial relation between the substrate angle, the development of color zones, film coverage and film thickness is discovered. The color range of the photonic films can be shifted by tuning the size distribution of CNC particles is also demonstrated. As the CNC particles and tactoids are deposited on the substrate, a central deformation line emerged with tilted and folded domains, which is a consequence of Marangoni flow-induced deformation of the tactoids at the early stages of deposition. Further in the process, well-aligned domains emerged at the bottom of the substrates, indicating the simultaneous kinetic onset of multiple gelation processes which depend on size segregation across different color zones. Such insights allow us to tune the color domains using angular deposition and manipulate the kinetic arrest phase transition to produce more uniform and homogeneous films.
纤维素纳米晶体（CNCs）可以自发地自组装成具有鲜艳颜色的胆甾相光子薄膜，这些薄膜具有多畴结构和胆甾相螺距的变化。在此，采用角沉积技术利用毛细管流和马兰戈尼流来制备具有从红色到蓝色空间可调结构颜色的CNC光子薄膜。发现了基板角度、色区发展、薄膜覆盖率和薄膜厚度之间的关键关系。还证明了通过调节CNC颗粒的尺寸分布可以改变光子薄膜的颜色范围。当CNC颗粒和类晶体沉积在基板上时，出现了一条中央变形线，伴有倾斜和折叠的畴，这是沉积早期马兰戈尼流引起类晶体变形的结果。在该过程的后期，基板底部出现了排列良好的畴，这表明多个凝胶化过程同时发生动力学起始，这取决于不同色区的尺寸分离。这些见解使我们能够利用角沉积来调节色区，并操纵动力学阻滞相变以产生更均匀的薄膜。
