胆甾相液晶微球光子禁带的动态调控及其应用  

Dynamic Manipulation of Photonic Bandgaps in Cholesteric Liquid Crystal Microdroplets for Applications

作　　者：刘晓珺 秦朗 俞燕蕾[1,2] Xiaojun Liu;Lang Qin;Yanlei Yu(Department of Materials Science,State Key Laboratory of Molecular Engineering of Polymers,Fudan University,Shanghai 200433,China;Yiwu Research Institute of Fudan University,Yiwu 322000,Zhejiang Province,China)

机构地区：[1]复旦大学材料科学系,聚合物分子工程国家重点实验室,上海200433 [2]复旦大学义乌研究院,浙江义乌322000

出　　处：《物理化学学报》2024年第5期3-23,共21页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(52173110);上海市自然科学基金(21ZR1405900);上海市青年科技启明星计划(22QA1401200)资助项目。

摘　　要：胆甾相液晶微球是空间结构高度对称的三维光子晶体,能够全方位地选择性反射特定波长的圆偏振光,具有无角度依赖性的光子禁带,作为一种新兴的光学材料在全向激光器、反射式显示和微传感器等领域展现出广阔的应用前景。近年来,毛细管微流控技术的蓬勃发展为连续、可控、高通量地制备结构复杂且分子规则取向的单分散胆甾相液晶微球提供了强有力的支持。本综述重点关注利用毛细管微流控技术制备胆甾相液晶微球的相关研究工作,首先分析了毛细管微流控装置在设计微球结构中的决定性作用,阐明了溶液体系的选择与液晶分子取向间的关系以及边界效应对微球尺寸的影响;随后,从胆甾相液晶微球的光学特性切入,介绍了利用温度、溶剂和光等外界刺激调控螺旋结构自组装的原理和策略以及微球之间独有的“光子交叉通讯”现象;最后,总结了现阶段胆甾相液晶微球的潜在应用方向并讨论了该材料体系未来面临的挑战。Cholesteric liquid crystal(CLC)microdroplets,as three-dimensional photonic crystals,exhibit high spatial symmetry.In these microdroplets,LC molecules are aligned parallel to the surface of the spherical geometry,while the helical axes are radially oriented.This symmetrical helical superstructure arrangement forms a Braggonion structure within the CLC microdroplets,resulting in selective reflection of a specific wavelength in all directions.Due to their unique angle-independent photonic bandgap(reflection wavelength),CLC microdroplets have emerged as promising optical materials for applications such as omnidirectional lasers,reflective displays,and microsensors.Recently,there has been growing interest in capillary microfluidic technologies,which allow the fabrication of monodisperse and complex CLC microdroplets with regular molecular alignment in a continuous,controllable,and highthroughput manner.This review primarily focuses on CLC microdroplets fabricated using capillary microfluidic technologies.Firstly,the characteristics of capillary microfluidic technology are outlined,along with three important parameters for fabricating CLC microdroplets:inertial,viscous,and interfacial forces.Capillary microfluidic devices typically consist of hydrophilic or hydrophobic tapered capillaries inserted into a square capillary.The principle of immiscible liquids is utilized to select suitable solution systems.By designing the device structures and choosing appropriate solution systems,single,double,triple,and even multiple CLC microdroplets can be fabricated.Secondly,the optical properties of CLCs confined in spherical geometries are discussed.CLC self-organizes into ordered helical superstructures while maintaining fluidity,leading to symmetrical pitch lengths in CLC microdroplets that respond to stimuli.The mechanisms and strategies for tuning the structural colors of CLC microdroplets under varying temperatures,solvents,and light conditions are demonstrated.Additionally,the unique photonic cross-communication between clos

关 键 词：胆甾相液晶 结构色 微流控 微球 光子器件 

分 类 号：O648[理学—物理化学]