1、Chem.J.Chinese Universities,2023,44(2),2022047420220474(1/13)CHEMICAL JOURNAL OF CHINESE UNIVERSITIES高 等 学 校 化 学 学 报综合评述纤维素纳米晶的空间受限自组装:从胶体液晶到功能材料段一雄，杨柏，李云峰（吉林大学化学学院,超分子结构与材料国家重点实验室,长春 130012）摘要 作为最有前途的生物衍生材料之一,纤维素纳米晶体(CNCs)具有来源广泛、生物相容性好和可形成光子结构等优点,在能源、生物医学和光子材料领域具有重要的应用价值.本文总结了CNCs的制备、CNCs形成的胆甾型胶体液晶
2、及CNCs衍生的光子材料的研究进展，重点评述了CNCs在液滴和毛细管中的自组装和基于CNCs空间受限组装的功能材料研究进展，并讨论了空间受限CNCs自组装研究面临的挑战和未来的发展方向.关键词 纤维素纳米晶；空间受限；自组装；胶体液晶中图分类号 O631 文献标志码 A doi：10.7503/cjcu20220474Self-assembly of Cellulose Nanocrystals in Spatial Confinement：from Colloidal Liquid Crystals to Functional MaterialsDUAN Yixiong，YANG Bai，L
3、I Yunfeng*（State Key Laboratory of Supramolecular Structure and Materials，College of Chemistry，Jilin University，Changchun 130012，China）Abstract Cellulose nanocrystals（CNCs），as one of the most promising bioderived materials，have many important applications in the fields of energy，biomedicine and phot
4、onic materials because of their abundance，biocompatibility，and ability to form photonic structures.This perspective highlights the recent advances in the self-assembly of CNCs in spatially confined geometry.We review the preparation of CNCs，the cholesteric liquid crystal formed by CNCs，photonic mate
5、rials derived from CNCs，self-assembly of CNCs in the droplets and cylindrical capillary and functional materials based on the confined assembly of CNCs，and discuss the new research directions in the self-assembly of CNCs in spatial confinement.Keywords Cellulose nanocrystal；Spatial confinement；Self-
6、assembly；Colloidal liquid crystal1 IntroductionCellulose nanocrystals（CNCs）have become promising building blocks for the preparation of many nanomaterials due to their inherent renewability，sustainability，and abundance13.The functional materials based on CNCs have been widely used in the field of pl
7、asmonic chiral materials4，sensors5，6，biomedicine710，energy11，12，catalysis13，and environmental science1418.CNCs are mainly prepared via 收稿日期：2022-07-11.网络首发日期：2022-08-30.联系人简介：李云峰,男,博士,教授,主要从事高分子胶体自组装和生物材料研究.E-mail:基金项目：国家自然科学基金(批准号:21972054)和吉林省自然科学基金(批准号:20220101204JC)资助.Supported by the National N
8、atural Science Foundation of China(No.21972054)and the Natural Science Foundation of Jilin Province,China (No.20220101204JC).CHEMICAL JOURNAL OF CHINESE UNIVERSITIES高 等 学 校 化 学 学 报综合评述Chem.J.Chinese Universities,2023,44(2),2022047420220474(2/13)the acid hydrolysis of the amorphous domains of cellulo
9、se fibers to obtain crystalline domains1.CNCs have rod-like structures with a high aspect ratio，which makes them ideal building blocks for the formation of cholesteric（chiral nematic）liquid crystals（LCs）.In general，the CNCs suspension in a glass vial undergoes phase separation into a cholesteric LC
10、bottom phase and an isotropic top phase19.Initially，CNCs assemble into a small anisotropic droplet（tactoid）with cholesteric packing of CNCs19.These tactoids then coalesce and merge into the cholesteric LC phase20，21.Chiral nematic LCs self-assembled from CNCs have been extensively studied as photoni
11、c materials22，templates23，responsive materials24 and reconfigurable materials25.Recently，the self-assembly of CNCs in confined spaces has attracted many interests in the fundamental research of soft matter and the exploration of innovative materials.In particular，the spatially confined assembly of C
12、NCs provides a valuable platform for the fundamental studies of particle packing26，self-assembly27，28，relaxation of colloidal liquids29，30 and topological defects31，32.Furthermore，confined assembly of the CNC cholesteric LCs provides a unique host template for the nanoparticle organization to prepar
13、e complex nanostructures3133.The self-assembly of CNCs in confined spaces also enables the fabrication of cholesteric microgels13，microfibers34 and microparticles31 with photonic properties.Although recently some reviews have summarized the macroscopic LCs of CNCs and photonic crystals of CNCs16，19，
14、there are few research summaries of the self-assembly of CNCs in spatial confinement.In this review，we provide a comprehensive review of the self-assembly of CNCs in spatial confinement.We first review the preparation of CNCs and the research progress of the macroscopic LCs and photonic films assemb
15、led from CNCs.Subsequently，we summarize the self-assembly of CNCs in the spatial confinement and their co-assembly with other nanoparticles.We also review the fixation methods and their emerging applications of CNCs in spatial confinement，and discuss the current challenges and prospects of the self-
16、assembly of CNCs in spatial confinement.2 Cellulose NanocrystalsThe cellulose in the cell wall of plants shows the fibril form.The cellulose fibers consist of a bundle of nanofibers which are composed of elongated parts of a single crystal of cellulose separated by amorphous cellulose regions14.Amorphous domains in cellulose nanofibers are more vulnerable and preferentially attacked by an acid to release crystal domains to obtain CNCs1.Normally，the CNCs were extracted by using acid hydrolysis wi
