Department of Chemistry, University of British Columbia , 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
FPInnovations , 2665 East Mall, Vancouver, British Columbia V6T 1Z4, Canada.
Langmuir. 2018 Jan 16;34(2):646-652. doi: 10.1021/acs.langmuir.7b03920. Epub 2017 Dec 29.
The self-assembly process in cellulose nanocrystal (CNC) film formation was studied as a function of evaporation time. It is known that the total evaporation time of CNC dispersions affects the structure of the film obtained, but the extension of different phases of the evaporation has not been explored. By extending the evaporation time of CNC suspensions after the onset of liquid crystallinity, the homogeneity of the resulting films could be improved as observed by polarized optical microscopy and scanning electron microscopy. Here, we show that an intermediate stage of self-assembly, between phase separation and gel vitrification, called tactoid annealing, helps explain the discrepancies in order for chiral nematic CNC films dried at varying evaporation times. This intermediate stage of self-assembly may be useful for designing highly ordered and homogenous CNC-based materials.
纤维素纳米晶体（CNC）薄膜形成过程中的自组装过程作为蒸发时间的函数进行了研究。众所周知，CNC 分散体的总蒸发时间会影响所获得的薄膜的结构，但尚未探索不同蒸发阶段的扩展。通过在液晶相开始后延长 CNC 悬浮液的蒸发时间，可以改善所得薄膜的均一性，这可以通过偏光显微镜和扫描电子显微镜观察到。在这里，我们表明，在相分离和凝胶玻璃化之间的自组装中间阶段，称为向列型 tactoid 退火，有助于解释在不同蒸发时间下干燥的手性向列型 CNC 薄膜的有序性差异。这种自组装的中间阶段对于设计高度有序和均匀的基于 CNC 的材料可能是有用的。
