新型聚合物纳米粒子的结构设计与合成方法研究

发布时间：2018-05-03 17:25

本文选题：纳米粒子 + 空心球　；参考：《中国科学技术大学》2017年硕士论文

【摘要】：聚合物纳米材料的设计、合成与应用,是在全球范围内受到极大关注的前沿课题之一。聚合物纳米材料,是指至少有一个维度的尺寸处在纳米级别的聚合物材料,从几何形状上讲,有球状、棒状、管状、线状、树枝状、层状等等。聚合物纳米粒子指的是形状为球形或近似球形的聚合物纳米材料,其形貌有实心球、空心球、多孔球、胶囊、囊泡、哑铃状、洋葱状等。聚合物纳米粒子的尺寸,处在原子簇和宏观物体之间的过渡区域,即处在宏观与微观之间的介观尺度上。因此,聚合物纳米粒子具有一系列独特的性质,例如表面效应、体积效应、量子尺寸效应、宏观量子隧道效应等。此外,相对于无机纳米粒子,聚合物纳米粒子还具备良好的分子水平上的可设计性。通过单体、合成路线、聚合方法的选择,可以精确操控聚合物纳米粒子的结构与官能团,使其具备特殊的功能,比如传感功能、催化功能、刺激响应功能、存储功能、载药功能等。这些功能与特性,使得聚合物纳米粒子在化学化工、生物医学、电磁学、光学、材料学、环境保护等领域有着广泛的应用前景。在聚合物纳米粒子的合成领域,已有大量的研究工作存在。但是,现有的合成方法,尚具有不足之处。一方面,对于聚合物纳米粒子结构和官能团位置的精确控制,仍然比较困难;另一方面,部分合成方法,步骤过于繁琐、条件过于苛刻,不易实现。因此,我们需要开发更为合理有效的设计思路与合成方法。为此,我们开展了以下三个方面的研究工作:1、我们利用聚合物分子刷的分子内季铵化交联反应,合成了聚合物纳米粒子,并实现了 “粒子单体”之间的聚合。利用可逆加成-断裂链转移(RAFT)聚合与一价铜催化的叠氮-炔的点击反应,通过graftingonto途径,我们设计并合成了核壳结构的聚合物分子刷。这些聚合物刷的侧链,具有两嵌段结构,靠近主链的内侧嵌段,含有一定比例的4-乙烯基吡啶(4VP)重复单元。利用这些4VP重复单元,我们可以加入卤代烃交联剂,实现聚合物刷的分子内季铵化交联,从而使一个聚合物刷“坍缩”成为一个聚合物纳米粒子。侧链的外侧嵌段是聚苯乙烯(PS)嵌段,该PS嵌段不参与分子内的交联反应。在溶液中,外侧的PS嵌段可以起到隔离保护作用,避免多个聚合物刷发生分子间交联。聚合物刷主链的两个末端,各含有一个羧基。利用这些羧基,我们可以把纳米粒子相互连接起来,得到链状结构。这个过程类似于单体发生聚合反应的过程。在该过程中,纳米粒子的行为,与小分子单体类似,可以称之为“粒子单体”。2、我们利用紫外光照射,在温和的条件下,高效地实现了聚合物分子刷的分子内交联,合成了官能团位置可控的聚合物纳米粒子。利用RAFT聚合,通过grafting from途径,我们设计并合成了核壳结构的聚合物分子刷。这些聚合物刷的侧链是两嵌段结构,内侧嵌段含有一定比例的叠氮基团,在紫外光照射下,可以发生氮烯插入反应;外侧嵌段由PS构成,起到避免分子间交联的作用。该聚合物刷在稀溶液中,受到一定时间的紫外光照射后,发生分子内交联,使得一个聚合物刷“坍缩”成为一个聚合物纳米粒子。在每个纳米粒子的表面上,含有一个露出的羧基。利用该羧基,我们可以将纳米粒子两两连接起来,形成了二聚体结构。这个裸露在外的羧基,可以进行进一步的化学修饰,为功能材料的制备提供了可能性。3、我们设计并合成了两亲性的引发转移终止(inifeter)试剂2-(N,N-二羧甲基二硫代氨基甲酸酯基)十二烷基异丁酸酯(DIBDC),并将该inifeter试剂分子末端的羧基转变成羧酸钠,用作表面活性剂,在醋酸铜(Cu(OAc)2)的催化下,通过细乳液聚合,制备了纳米级别的聚苯乙烯空心球。在该聚合过程中,Cu(OAc)2不会进入油相液滴内部,二硫代氨基甲酸酯基团则起到了假卤素引发剂的作用,使得引发过程只发生在油水界面上;由于iniferter试剂的链转移作用,增长反应也只发生在油水界面上。因此,整个聚合过程都不会发生在液滴内部,只会发生在油水界面上,从而生成了中空聚合物球。该方法简便易行,且从原理上避免了实心聚合物粒子的形成。
[Abstract]:The design, synthesis and application of polymer nanomaterials is one of the frontiers of great concern worldwide. Polymer nanomaterials are polymer materials at least one dimension at the nanometer level. From the geometry, there are spherical, rod, tubular, linear, dendritic, layered and so on. Polymer nanoparticles. The subsurface is a spherical or approximately spherical polymer nanomaterial with solid spheres, hollow spheres, porous spheres, capsules, vesicles, dumbbell shaped, onions, etc. the size of the polymer nanoparticles is in the transition region between the cluster and the macroscopic object, that is, at the mesoscopic scale between the macro and the microcosmic. The grain of rice has a series of unique properties, such as surface effect, volume effect, quantum size effect, macroscopic quantum tunneling effect, etc.. In addition, the polymer nanoparticles have good molecular design in relation to inorganic nanoparticles. The polymer can be accurately manipulated through the selection of monomer, route and polymerization method. The structure and functional groups of nanoparticles have special functions, such as sensing function, catalytic function, stimulating response function, storage function, drug loading function and so on. These functions and characteristics make polymer nanoparticles widely used in chemical, biomedical, electromagnetics, optics, materials science, environmental protection and other fields. There are a lot of research work in the field of synthesis of polymer nanoparticles. However, the existing synthetic methods are still inadequacies. On the one hand, it is still difficult to control the structure of polymer nanoparticles and the position of functional groups. On the other hand, the partial combination method is too complicated, the conditions are too harsh and uneasy. Therefore, we need to develop more reasonable and effective design ideas and synthetic methods. To this end, we have carried out the following three aspects of research: 1, we have synthesized polymer nanoparticles by using the intramolecular quaternized crosslinking reaction of polymer molecular brushes, and realized the polymerization between the "particle monomer". Fracture chain transfer (RAFT) polymerization and clicking reaction of azide alkyne catalyzed by one valence copper, through the graftingonto pathway, we designed and synthesized the polymer molecular brushes of the nuclear shell structure. The side chains of these polymer brushes have two block structures, close to the inner block of the main chain, and contain a certain proportion of 4- vinyl pyridine (4VP) repeating units. In these 4VP repeating units, we can add the halogenated hydrocarbon crosslinking agent to realize the intramolecular quaternated crosslinking of the polymer brush, thus making a polymer brush "collapsing" into a polymer nanoparticle. The lateral chain of the side chain is polystyrene (PS) block, and the PS block is not involved in the intramolecular crosslinking reaction. In the solution, the lateral PS inlay. The segment can act as an isolated protection to avoid intermolecular crosslinking of multiple polymer brushes. The two ends of the main chain of the polymer brush each contain a carboxyl group. Using these carboxyl groups, we can connect the nanoparticles to the chain structure. This process is similar to the monomer polymerization process. In this process, nanoscale The behavior of particles, similar to small molecule monomers, can be called "particle monomer".2. We use ultraviolet light to effectively achieve intramolecular cross-linking of polymer molecular brushes and synthesize polymer nanoparticles with controllable functional group position under mild conditions. By polymerization of RAFT, we design and combine the grafting from pathway. The polymer brush is a nuclear shell structure. The side chain of these brushes is two block structure, the inner block contains a certain proportion of azide group. Under ultraviolet light, the azenene insertion can occur. The lateral block is made up of PS, which prevents intermolecular crosslinking. The polymer is brushed in dilute solution for a certain time. After ultraviolet light, intramolecular crosslinking makes a polymer brush "collapse" into a polymer nanoparticle. On the surface of each nanoparticle, it contains an exposed carboxyl group. Using the carboxyl group, we can connect the nanoparticles 22 together to form a two polymer structure. One step of chemical modification provides a possibility for the preparation of functional materials. We designed and synthesized a two Pro activation transfer termination (inifeter) reagent 2- (N, N- two carboxymethyl two thiocarbamate) twelve alkyl isobutyl ester (DIBDC), and the carboxyl group of the molecular terminal of the inifeter reagent into sodium carboxylate as a surface. Under the catalysis of copper acetate (Cu (OAc) 2), the nanoscale polystyrene hollow sphere was prepared under the catalysis of copper acetate (Cu (OAc)). In the process of polymerization, Cu (OAc) 2 did not enter the oil droplet, and the two thiocarbamate group acted as a pseudo halogen initiator, making the initiation process only on the oil-water interface; because ini The effect of ferter reagent on the chain transfer is only on the oil and water interface. Therefore, the whole polymerization process will not occur inside the droplets, but it will only occur on the oil-water interface, thus forming a hollow polymer ball. This method is simple and easy, and the formation of solid polymer particles is avoided in principle.

【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O631

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