【作者】 王竞；

【导师】 江明；

【作者基本信息】 复旦大学 ， 高分子化学与物理， 2007， 博士

【摘要】 基于包结作用的高分子及纳米晶体自组装的研究超分子化学中的核心问题是分子自组装，这是指构筑基元借助于分子间力自发地形成有序结构。构筑基元可以是无机分子，有机小分子，高分子，以及生物大分子等。在分子自组装的多种驱动力中，主—客体包结络合作用占有重要的地位，环糊精（Cyclodextrin）是第二代主体化合物的代表，其空腔可以包结多种分子，它已被深入研究。特别是，β-环糊精和金刚烷因其包结络合常数高达10⁵，被科学家们应用到各个领域。近年来我们课题组建立了一种构建聚合物胶束的非嵌段共聚物路线，由此可采用均聚物对作为组装单元，这样连接聚集体胶束的壳和核层的作用力是氢键而不是化学键，这种方法形成的就是“非共价键接胶束”（NCCM）。用来构筑NCCM的驱动力通常为氢键、疏水相互作用或范德华力等等，本论文在此基础上开展，将环糊精—金刚烷的包结络合作用引入到我组大分子自组装的研究中，论文可分为以下几个方面：一：我们将β-环糊精和金刚烷分别引入到两种高分子链段，使它们组装成为非共价键胶束。含金刚烷的疏水高分子PtBA-ADA形成核，而含环糊精的水溶性高分子PGMA-CD成壳，核壳之间由环糊精和金刚烷的包结力稳定。将胶束壳交联，然后除去内核，我们可以获得只由环糊精聚合物组成的空心球。这样获得的空心球不仅含有尺寸在几百纳米的空心，而且还含有大量的环糊精空穴，其尺寸在0.7纳米左右，由此我们就获得了具有含不同尺度疏水空穴的空心球结构。它们在负载和释放方面具有独特的应用。无论是上述胶束或空心球，因表面存在环糊精空穴，我们可以方便对其进行表面修饰，得到带正电荷或者负电荷的聚集体。二：纳米粒子的有序结构是纳米功能材料制备研究工作的重要方面，水—油界面对纳米粒子的排列有促进引导作用，在此类不相容溶剂的界面上，纳米粒子仍然保持很好的流动性。本文中我们将环糊精和金刚烷的包结作用力作为界面组装的驱动力引入到纳米粒子组装体系中来，首先将金刚烷修饰到磁性纳米晶体CoPt₃或Fe₃O₄表面，将此类疏水纳米粒子溶解在如甲苯等有机溶剂中，然后将其与环糊精水溶液混合。借助于纳米晶体表面的金刚烷基团与环糊精的包结络合作用，纳米晶体会从甲苯相中转移到水和甲苯的界面相上，且大量的纳米晶体堆积形成了纳米粒子的单层膜。进一步地，我们还用含有氨基、巯基等活性基团的环糊精衍生物修饰金、银纳米粒子，从而可以将这些金属纳米晶体再吸附到已经形成的磁性纳米晶体膜表面，由此获得了两层、三层的复合纳米晶体组装膜，这种逐层自组装制备的多层膜具有磁性，光学性能等多种特性。三：刚性大分子组分的引入可以诱导发生特殊的自组装行为。本文中我们合成了低分子量的端羧基聚酰亚胺，它可通过pH诱导自组装，在水相中微相反转形成多种形态的单组分聚合物组装体，即“酒窝”型、多孔聚集体和囊泡等。对此我们采用DLS、SEM、TEM和ζ—电位等多种测试手段对聚集体的形态和尺寸进行表征，并讨论了聚集体多种形态形成机理。四：本章研究发光共轭聚合物刚性链的自组装，首先将金刚烷修饰到低分子量的聚芴端基处，然后利用β-环糊精和金刚烷的包结络合力在水相中诱导聚合物的自组装。如果采用可与聚芴形成“荧光给体—受体”的荧光素来修饰环糊精，并将其水溶液诱导聚芴进行自组装，荧光素基团和聚芴主链由于环糊精和金刚烷的包结作用能互相接近，发生荧光共振能量转移（FRET）效应。我们对这种包结络合诱导荧光能量转移进行了研究。五：环糊精聚合物PGMA-CD和以PGMA-CD为壳的胶束，均有大量的环糊精空穴存在。我们研究了经金刚烷修饰的染料分子通过包结络合与PGMA-CD聚合物及相应胶束的结合和相应的荧光淬灭。再通过超分子取代反应，实现染料分子的释放和荧光回复。这部分的工作是为今后将包结络合作用应用于荧光生物检测的研究打下基础。更多还原

【Abstract】 Studies on Polymeric and NCs Self-assembly via Inclusion InteractionMolecular self-assembly, the most important area in suprachemistry, means spontaneous building-up of complex structures via intermolecular interaction, from various building blocks including inorganic and organic molecules and macromolecules, etc. Among different kinds of driving forces leading to self-assembly, the host-guest inclusion plays an important role. Cyclodextrins （CD） seem to be the most extensively studied host compounds characteristic of a hydrophilic exterior surface and hydrophobic interior cavity, which can accommodate a wide range of molecules as guests. Among the varieties of such host-guest pairs,β-CD and adamtantly group （ADA） has been mostly investigated due to their high association constant （～10⁵）.In recent years our group has developed ’block-copolymer-free strategies’ to fabricate polymeric micelles using polymer pairs as building blocks. These novel approaches result in noncovalently connected micelles （NCCM）, in which intermolecular specific interactions （hydrogen bonding and hydrophobic interaction etc.） rather than chemical bonding exist between the shell and core. Being a substantial progress in the studies on NCCMs, in this thesis we investigate a series of new self-assembly systems including polymeric micelles and hollow spheres and structured films of nanocrystals, by introducing the inclusion complexes ofβ-CD and adamantane into our work. The thesis is constituted of five parts:Firstly, a hydrophilic polymer PGMA-CD containingβ-CD and hydrophobic ADA-containing polymer PtBA-ADA were used as building blocks to construct micelles. Driven by the inclusion interaction betweenβ-CD and ADA, the micelles in aqueous media with PtBA-ADA as the core and PGMA-CD as the shell are formed. The resultant micelles stably dispersed in water possess unique characters: it contains both a hydrophobic PtBA-ADA core on a scale of hundreds of nanometers and hydrophobic cavities of CD in a size of 0.7 nm in the shell. Taking advantages of the cavities being able to accommodate different molecules, the micellar surface can be easily modified to either hydrophobic or charged ones. Besides, by subsequently crosslinking the shell and dissolving the core, the micelles can be converted toβ-CD-containing nanocages. The resultant hollow spheres contain multi-scale holes: the large central one andβ-CD interior cavities. These CD cavities provide a broad range of opportunities for further surface modifications of the micelles or hollow spheres by incorporating different kinds of functional molecules. Thus, a neutral surface is converted to an anionic or a cationic surface via the inclusion interaction between the CD cavities and adamantly groups.Secondly, the self-assembly of inorganic nanocrystals （NCs） into hierarchical structures is pivotal in preparation of nano-functional materials. The interfacial ordering effects in NCs arrangement can be utilized since good fluidity of NCs is kept on the immiscible liquid-liquid interface. Herein, interfacially self-assembly of NCs is demonstrated driven by the inclusion interaction betweenβ-CD and adamantyl groups. The hydrophobic NCs （CoPt₃, Fe₃O₄） with surface modified by adamantyl groups dispersed in organic solvent, i.e. toluene, was mixed withβ-CD water solution. A phase transition of NCs would occur from toluene to water/oil interface via the inclusion interaction from adamantyl groups on NCs surface andβ-CDs. Furthermore,β-CDs functionalized with one SH or NH₂ group were recruited as new ligands to direct consecutively metal NCs（Ag, Au） onto magnetic monolayers of CoPt₃ or Fe₃O₄ NCs between water/oil interface. Thus, these heterogeneous bi- or trilayers composed of different NCs may be generated, which possess novel optical and magnetic properties.Thirdly, we concentrate on self-assembly of rigid low-molecular-weight polyimide with two carboxyl ends （CPI） via microphase inversion by adding water with different pH into CPI/THF solutions. The aggregates with multiple morphologies including dimpled-beads, porous spheres and vesicles were obtained and investigated by TEM, SEM, DLS andζ-potential technologies. The rigid structure of CPI plays an important role in the formation of the multiple morphologies.In the fourth part, we present self-assembly of luminescent conjugated polymer via inclusion interaction betweenβ-CD and adamantane. Aggregates are fabricated by addingβ-CD water solution into low-molecular-weight polyfluorene （PF） with adamantyl-terminated group （PF-ADA） in THF. The luminescent polymer PF-ADA acts as fluorescent donor while fluorescent dye fluorescein as an acceptor. Therefore, CD-FITC, a CD derivative containing fluorescein group, is used to induce the self-assembly of polyfluorene. FRET （fluorescence resonance energy transfer） behavior of the assembly was investigated as FITC and polyfluorene are close to each other.Finally, great deals of CD cavities remain intact in both CD polymer （PGMA-CD） and the micelles with PGMA-CD as the shell. Two ADA modified fluorescent dyes, fluorescein and rhodamine, were synthesized and used to investigate the dye loading onto the CD polymer chain or micelle surface. The inclusion complexation of the modified dyes and CD causes fluorescent quenching. Afterwards dye release and fluorescence recovery could be realized by supramolecular replacement, i.e. the dye molecule is excluded from the CD cavities by adding excess ACA （1-adamantylcarboxylic acid）. Our work provides wide potential for introducing the inclusion interaction into fluorophore-based biodetection field in future research.更多还原