Sewring Tor, Dijkstra Marjolein
Soft Condensed Matter & Biophysics, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands.
International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM2), Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
J Chem Phys. 2023 Nov 21;159(19). doi: 10.1063/5.0167362.
Using Onsager-Straley's second-virial theory, we investigate the cholesteric pitch of cellulose nanocrystal (CNC) suspensions. We model the CNCs as hard chiral bundles of microfibrils and examine the effect of the shape of these chiral bundles, characterized by aspect ratio and chirality, on the cholesteric pitch. Additionally, we explore the impact of length polydispersity and surface charge on the cholesteric phase of CNCs. Furthermore, we consider binary mixtures of twisted bundles and achiral primary crystallites to provide a more realistic representation of CNC suspensions. Our findings reveal that the degree of bundle twisting significantly affects the helical twisting of the cholesteric phase. We also observe that the average particle length and length polydispersity have substantial effects on strongly twisted bundles but minimal effects on weakly twisted ones. Finally, our study indicates that as the range of electrostatic interactions increases, the transfer of chirality from the microscopic to macroscopic length scales becomes masked, resulting in an increase in the cholesteric pitch. In the case of binary mixtures, the bundles act as chiral dopants, and an increasing fraction of bundles progressively enhances the helical twisting of the cholesteric phase.
利用昂萨格 - 斯特拉利的第二维里理论，我们研究了纤维素纳米晶体（CNC）悬浮液的胆甾相螺距。我们将CNC建模为微纤丝的硬手性束，并研究这些手性束的形状（以纵横比和手性为特征）对胆甾相螺距的影响。此外，我们探讨了长度多分散性和表面电荷对CNC胆甾相的影响。此外，我们考虑了扭曲束和非手性初级微晶的二元混合物，以更真实地表示CNC悬浮液。我们的研究结果表明，束的扭曲程度显著影响胆甾相的螺旋扭曲。我们还观察到，平均颗粒长度和长度多分散性对强扭曲束有显著影响，而对弱扭曲束的影响最小。最后，我们的研究表明，随着静电相互作用范围的增加，手性从微观到宏观长度尺度的转移变得模糊，导致胆甾相螺距增加。在二元混合物的情况下，束充当手性掺杂剂，束的比例增加会逐渐增强胆甾相的螺旋扭曲。
