【作者】 吕强；

【导师】 郑敏； 廖良生；

【作者基本信息】 苏州大学 ， 纺织科学与工程， 2023， 博士

【摘要】 有机荧光染料分子的低维结构作为一种优异的光学晶态材料,将其引进纺织纤维材料中,不仅可以拓宽有机低维晶态材料的应用领域,而且有助于制得更加色彩鲜艳和功能化纺织品。特别是具有复杂结构的有机低维晶体为光子调制及其光学加密提供了新途径。但是,分子间弱的非共价相互作用会导致有机晶体成核及生长难以控制,所以开发低维晶态结构的可控构筑策略并揭示其构效关系对于发展高性能有机荧光材料十分必要。本论文通过溶液自组装方法制备了一系列具有荧光发射可调性能的有机共晶及合金材料,进一步从满足不同应用场景的需求出发制备了掺杂纳米纤维膜及异质结构微米线,并探索其在功能织物和光学波导中的光功能应用。主要研究内容分为以下几个方面:（1）通过简单高效的溶液自组装方法设计合成了一系列有机共晶材料,探究有机给受体分子对有机共晶的制备及光学性质的影响,从而揭示分子结构与晶体光学性能之间的构效关系。基于有机分子能级结构及分子间作用力的调控,构筑了系列有机共晶材料,实现吸收范围在300～1800 nm和荧光发射范围在400～1015 nm间的灵活调控。进一步,基于有机共晶相似的分子间距离、堆积方式以及竞争性的分子间相互作用,可控制备了兼具荧光发射可调及增强荧光量子产率性能的有机合金材料。（2）从构建功能织物的应用角度出发,通过静电纺丝技术将有机共晶或合金材料掺杂进入聚氨酯（PU）纳米纤维膜中,实现具有可见到近红外波段的荧光发射薄膜材料,探索了掺杂纳米纤维膜的制备条件及晶体在纤维中存在形式。进一步将具有近红外吸收的有机共晶掺杂进PU纳米纤维膜中,实现光热转换效率达到60%的优异性能。此研究证明了有机低维晶体与纺织纤维材料复合的可行性,从而填充了有机晶体材料掺杂纳米纤维膜研究领域的空白。（3）为解决当前单一结构的有机共晶无法满足微观层面上光子调制的问题,深入探究多组分自组装过程中有机共晶的晶体结构及晶面吸附能对异质结构可控制备的影响,提出了一种有机异质结构的超低晶格失配外延生长策略。通过该策略可控制备了具有超低晶格失配率（η）的三嵌段（η₁=0.7%）、枝杈（η₂=0.8%）和核/壳（η₃=0.6%）异质结构微米线。最后,基于异质结构微米线位置依赖的发光特性,实现了主动与被动光波导及光学逻辑门运算。（4）针对有机异质结构微米线无法宏量制备而限制其实际应用的问题,提出了一种基于有机共晶及合金的无晶格失配生长概念,实现了有机异质结构微米线的大规模制备。进一步,通过调控物质比例实现了三嵌段和核壳结构微米线的精准构筑。随后,探究了该策略的普适性,研究发现通过合理选择有机分子可以实现十几种异质结构微米线的制备。最后,通过模板法限域嵌段结构微米线的生长制备了荧光二维码图案,并利用嵌段结构微米线的独特结构和光谱特征实现了二维码图案的三级加密。本策略为大规模、可控制备有机异质结构微米线提供了新途径,同时基于荧光二维码的防伪加密性能,为光学信息加密提供材料基础和理论依据。更多还原

【Abstract】 Low-dimensional structures of organic fluorescent dye molecules,as excellent optical crystalline materials,can be introduced into textile fibers to broaden the application field of organic low-dimensional crystalline materials and facilitate the production of more colorful and functional textiles.In particular,organic low-dimensional crystals with complex structures provide new avenues for photon modulation and information encryption.However,weak non-covalent interactions between molecules can make it difficult to control the nucleation and growth of organic crystals.Therefore,it is necessary to develop controllable construction strategies for low-dimensional crystalline structures and reveal their structure-property relationships for the development of high-performance organic fluorescent materials.In this paper,a series of organic cocrystal and alloy materials with tunable fluorescence emission were prepared by a simple and efficient solution self-assembly method.Furthermore,nano-fiber-doped films and heterogeneous microwires were prepared from the perspective of meeting the needs of different application scenarios,and their optical functional applications in functional fabrics and optical waveguides were explored.The main research contents are as follows:（1）In this paper,a series of organic cocrystal materials were designed and synthesized through a simple and efficient solution self-assembly method.The effects of organic donor-acceptor molecular interactions on the preparation and optical properties of organic cocrystals were explored,revealing the structure-property relationship between molecular structure and crystal optical properties.Based on the regulation of organic molecular energy level structure and intermolecular interactions,a series of organic cocrystal materials were constructed,achieving flexible control of absorption range between 300-1800 nm and fluorescence emission range between 400-1015 nm.Furthermore,based on the similar intermolecular distance,stacking mode,and competitive intermolecular interactions of organic cocrystals,organic alloy materials with tunable fluorescence emission and enhanced fluorescence quantum yield were controllably prepared.（2）Starting from the application perspective of constructing functional fabrics,this study explores the feasibility of compositing organic cocrystal or alloy materials into polyurethane（PU）nanofiber membranes through electrospinning technology,achieving thin film materials with visible to near-infrared fluorescence emission.The preparation conditions of doped nanofiber membranes and the existence form of crystals in fibers were investigated.Furthermore,organic cocrystal with near-infrared absorption was doped into PU nanofiber membranes,achieving excellent performance with a photothermal conversion efficiency of 60%.This study demonstrates the feasibility of compositing organic low-dimensional crystals with textile fiber materials,filling the gap in the research field of organic crystal materials doped nanofiber membranes.（3）To address the issue of single-structured organic cocrystals being unable to meet the requirements of photon modulation at the microscale,an investigation was conducted into the crystal structure and surface adsorption energy of organic cocrystals during the process of self-assembly with multiple components.This led to the proposal of a strategy for the controlled preparation of organic heterostructures with ultra-low lattice mismatch through epitaxial growth.Using this strategy,microwires with ultra-low lattice mismatch rates（η）were prepared,including three-block copolymers（η₁=0.7%）,branched structures（η₂=0.8%）,and core/shell structures（η₃=0.6%）.Finally,based on the position-dependent luminescent properties of the heterostructure microwires,active and passive optical waveguides and logical gates were realized.（4）To address the issue of the inability to mass-produce organic heterostructure microwires,which limits their practical applications,a concept of lattice-mismatch-free growth based on organic co-crystals and alloys was proposed,enabling the large-scale production of organic heterostructure microwires.Furthermore,precise construction of three-block copolymer and core/shell structure microwires was achieved by adjusting the material proportions.The universality of this strategy was investigated,and it was found that by choosing the appropriate organic molecules,over a dozen types of heterostructure microwires could be prepared.Finally,using a template method,fluorescent two-dimensional barcode patterns were prepared by growing block copolymer microwires with confined segment structures,and the unique structure and spectral features of the segment structure microwires were utilized to achieve triple encryption of the barcode pattern.This strategy provides a new way to mass-produce and control the preparation of organic heterostructure microwires,and the anti-counterfeiting encryption performance of the fluorescent two-dimensional barcode provides material basis and theoretical basis for optical information encryption.更多还原