【作者】 金岚；

【导师】 汪长春；

【作者基本信息】 复旦大学 ， 高分子化学与物理， 2005， 博士

【摘要】 近十几年来，具备单一功能的聚合物微球，如单分散聚合物微球、磁性微球、荧光微球、pH响应微球和温度响应微球等的制备技术日趋成熟。而随着生物医药、电子信息、新材料等应用领域的飞速发展，人们对功能性聚合物微球的要求开始趋于多元化，多功能化的聚合物微球开始受到广泛的关注，构筑多种功能复合的微球已经成为聚合物微球的重要研究方向之一。本论文在沿用了我们课题组在微球制备方面的功能模块化设计理念的基础上，通过两种途径来制备功能性聚合物微球，一种途径是从单分散的聚合物微球出发，首先对聚合物微球表面进行官能团改性，然后通过可控聚合方法在微球表面接枝功能性聚合物，制备壳层可控且功能化的聚合物微球。另一种途径是从两嵌段共聚物出发，利用功能性小分子或纳米粒子与嵌段聚合物功能基团的非化学键作用构成核层功能化的聚合物微球。通过上述两种构筑功能性微球的思路，我们合成了一系列具有不同功能的聚合物微球，并且对微球进行了动态激光光散射(DLS)、透射电镜(TEM)、扫描电镜(SEM)、热重分析(TGA)、傅立叶红外(FTIR)、凝胶渗透色谱(GPC)以及核磁共振(NMR)等表征，取得了以下几个方面的结果：1．以甲基丙烯酸甲酯(MMA)和甲基丙烯酸缩水甘油酯(GMA)为单体，二乙烯基苯(DVB)为交联剂，分别采用无皂乳液一步聚合方法制备了不交联及低交联度的具有良好单分散性的亚微米P(MMA-GMA)聚合物微球；采用无皂乳液两步聚合(即后滴加交联剂的无皂乳液聚合)方法制备了高交联度的亚微米P(MMA-GMA)聚合物微球，该微球同样具有良好的单分散性，但是微球表面形态有所变化。本文通过对不同交联度聚合物微球的形态及稳定性的表征，推测了无皂乳液两步聚合法的机理。2．为了制备具可自分散功能的单分散聚合物微球，本文在对不同交联度的P(MMA-GMA)聚合物微球进行表面氨基改性后，以氨基化的P(MMA-GMA)聚合物微球为反应核，交替进行Michael加成和酰胺化反应，接枝了树枝形的聚酰胺胺(PAMAM)。并且，接枝了七代PAMAM的聚合物微球就已经表现出了良好的自分散性。通过对不同交联度聚合物微球表面接枝PAMAM后的形态及粒径变化进行的一系列表征，证明了聚合物微球功能性壳层的厚度可以通过改变树枝形聚合物的接枝代数来控制；研究了不同pH值的情况下，不同交联度聚合物微球的形态变化与反应核本身交联度之间的关系。实验也发现，表面接枝高代数PAMAM的功能性聚合物微球质子化后可以吸附大量的磁流体，并具有良好的磁分离效果。该类微球也可以作为进一步功能化的微球平台。3．在单分散的亚微米无机二氧化硅微球表面进行氨基化改性，并以此二氧化硅微球为反应核，交替进行Michael加成和酰胺化反应，获得了表面接枝树枝形PAMAM的二氧化硅微球。经过FTIR，TGA等表征，证明PAMAM可以很好的接枝到二氧化硅微球表面，得到功能化的有机—无机杂化微球。4．制备了表面接枝线性功能性聚合物链的单分散聚合物微球。以不同粒径大小的单分散亚微米聚苯乙烯—聚乙酸乙烯酯(P(St-VAc))聚合物微球为核，采用氧阴离子聚合方法，在微球表面引发可质子化单体甲基丙烯酸-2-(N,N-二甲胺基)乙酯(DMAEMA)的聚合反应。通过改变单体的投料量，可以良好的控制壳层功能性聚合物的接枝量。功能化后的聚合物微球可以通过改变环境的pH值来改变聚合物微球表面的电荷性质，从而可以完成对带异性电荷的磁流体的吸附和脱附，这种聚合物微球可以用于生物分子的输送转运载体。5．采用胶束法制备了核层功能化聚合物微球。通过稀土金属Eu(Ⅲ)与丙烯酸(AA)的络合相互作用，制备了核层为稀土金属络合物，壳层为固定链长的聚乙二醇(PEG)的纳米荧光微球。通过荧光光谱等表征，研究了在不同溶剂环境中，不同[Eu]／[AA]比例下，聚合物微球的荧光强度及其变化规律。并且尝试了以表面带有羧基的半导体纳米粒子CdTe通过正负电荷作用，诱导双亲水性嵌段共聚物在水性环境中形成壳层可控的荧光纳米微球。更多还原

【Abstract】 The synthesis techniques of mono-functional microspheres, such as monodispersed microspheres, magnetic microspheres, fluorescent microspheres, pH-sensitive microspheres and thermo-sensitive microspheres, etc., have been developed very well over the last two decades. Due to the quickly development of functional microspheres in many applications, including biotech, electro-tech, IT and new materials et al., the preparation of functional microspheres was shifted from mono-functional microspheres to multi-functional microspheres. In this thesis, several kinds of functional microspheres were prepared, and two different synthetic routes were chosen to fabricate the microspheres. For the first route, mono-dispersed microspheres were prepared as the core particles at first. After the surface of these microspheres being modified with functional group, the controllable polymerizations were carried out on the surface of the microspheres to synthesize functional polymers, so that the shell-functionalized core-shell microspheres were fabricated. For the second route, di-block copolymers were prepared firstly. Functional micromolecules or nanoparticles coordinated with the functional groups of the di-block copolymers to fabricated core-functionalized core-shell nanospheres. All the functional micro- and nano-size spheres were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and nuclear magneticresonance (NMR), etc. The main results have been obtained as follows:(1) Monodispersed sub-micron microspheres were prepared via two different soap-free emulsion polymerization, of which, methyl methacrylate (MMA) and glycidyl methacrylate (GMA) were used as monomer and divinyl benzene (DVB) was used as cross-linker. The un-crosslinked and low-crosslinked microspheres were synthesized by one-step soap-free emulsion polymerization. The high-density crosslinked microspheres were synthesized by two-step soap-free emulsion polymerization, in which the crosslinker were added into reaction system after the polymerization was initiated for a fixed amount of time. Owning to the different synthetic methods, the microspheres possess different shapes and structures.(2) To preparation of self-dispersible polymer microspheres with monodispersed size, monodisperse P(MMA-GMA) copolymer microspheres were utilized as core-particles and dendrimer PAMAM were acted as the functional shell. Dendrimer PAMAM grafted from the microspheres by repeated Michael addition and amidation. The core-shell functional microspheres with 7-generations PAMAM shell possess good self-dispersibility. Different cross-linking densities of core microspheres influence on the integrity of the functional core-shell spheres after acid treated. Protonated core-shell microspheres could load a mass of acid-modified magnetic nanoparticles.(3) Monodispersed sub-micron silica microspheres, as the core particles of the functional microspheres, were prepared via Stober process. Dendrimer PAMAM grafted from the silica spheres by repeated Michael addition and amidation. It is confirmed from FTIR and TGA results that the PAMAM were grafted onto the silica spheres successfully. The core-shell organic-inorganic hybrid microspheres were fabricated.(4) A series of poly(styrene-vinyl acetate) (P(St-VAc)) crosslinked monodispersed microspheres (240, 210, or 90 run) with different concentrations of PS (75, 50, or 25 wt %) were prepared by soap-free emulsion polymerization. Based on the crosslinked polymer microspheres, three series of monodispersed core-shell microspheres with pH-sensitive poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) shells weresynthesized by oxyanionic polymerization. Because the PDMAEMA chain could be protonated at a low pH, these core-shell microspheres could adsorb negative-charged magnetite particles, and at higher pH, the magnetite particles could be released again, this process was reversible.(5) Coordination-induced micelles were prepared via rare earth metal Eu(III) with block copolymer of PEG-b-PAA. Since PEG and PAA were all hydrophilic polymer, the micellization was induced by the coordination of Eu(III) with block copolymer in aqueous solution. Fluorescence spectroscopy showed the formation of coordinative complex by bond Eu(III) - carboxyl of AA. The coordinated micelles were formed with hydrophilic PEG blocks and hydrophobic coordinative complexes. A study of the dependence of emission intensities of the Eu-copolymers on the Eu content showed that the emission intensities increased nonlinearly with increasing Eu content. The acid modified quantum dot (QD) CdTe was also utilized to coordinate with the amino-group of block copolymer PEG-PDMAEMA in aqueous solution. The TEM images showed that core-shell fluorescence nanospheres were fabricated.更多还原