【作者】 胡娜；

【导师】 陈明清；

【作者基本信息】 江南大学 ， 应用化学， 2013， 博士

【摘要】 活性自由基聚合具有反应条件温和、适用单体范围广等优势，近些年来受到研究者的广泛关注。目前活性自由基聚合的方法主要有引发转移终止剂（iniferter）法、氮氧自由基调控聚合（NMP）、稳定自由基聚合（SFRP）或过渡金属催化活性自由基聚合以及可逆加成断裂链转移聚合（RAFT）和原子转移自由基聚合（ATRP）。其中ATRP法因聚合反应速率高，反应温度适中，适用单体范围广，分子设计能力强而被广泛用于多种烯类单体的聚合，制备得到结构确定的均聚物与多种新型的嵌段、接枝等聚合物与有机/无机杂化材料。双亲性共聚物自组装的胶束形态受到许多因素的影响：如聚合物的化学结构、分子量、各链段的相对含量、链段的序列以及溶剂的性质等。鉴于组装体具有新奇的结构以及独特的性能，在医药、绿色环保材料、生物工程、纳米材料和医学诊断等方面具有广阔的应用前景。据此，本论文主要采用ATRP合成了多种不同结构组成的聚合物，并对共聚反应、胶束化行为和相关性能进行了较深入的探讨，主要包括以下几个方面：1.通过ATRP法一步法制备得到了分子量可控、分子量分布窄的端基含有双键的大分子单体聚4-乙烯基吡啶（St-P4VP），聚合反应过程具有ATRP活性聚合的特征，进而以St-P4VP大分子单体作为反应分散稳定剂，通过分散聚合制得了单分散的P4VP-g-PSt聚合物微球，深入研究了介质的极性、反应体系的温度、St-P4VP大分子单体的用量对微球粒径的影响，由于P4VP-g-PSt聚合物微球表面分布P4VP链段，使其具有pH响应性。将所得到的P4VP-g-PSt聚合物微球与Ag+进行复配，制备得到了Ag/P4VP-g-PSt聚合物复合微球，进而研究了复合微球的催化性能，以及对大肠杆菌与白色葡萄球菌的抗菌性能。2.通过ATRP法合成分子量可控、分子量分布窄的星形聚苯乙烯大分子引发剂（PSt-Br）4，进而以（PSt-Br）₄为大分子引发剂，引发第二单体N-异丙基丙烯酰胺（NIPAM）聚合，合成了双亲性星形嵌段共聚物（PSt-b-PNIPAM）₄。进而使（PSt-b-PNIPAM）₄在DMF/H₂O选择性溶剂中自组装形成胶束，研究了亲水链段PNIPAM的长度对胶束的粒径及LCST的影响。（PSt-b-PNIPAM）₄胶束可以作为Au纳米粒子的载体，通过胶束表面的PNIPAM链段与AuCl₄复配-还原制备得到Au/（PSt-b-PNIPAM）₄复合胶束，是一种具有温度响应性的催化体系。研究了此催化体系在NaBH₄还原对硝基苯酚为对氨基苯酚实验中的温度响应性，结果显示其与一般催化体系不同的特征，催化反应的速率可以通过改变催化体系的温度的而进行调节，具有可控的特点。通过调控体系的温度可将其进行回收，在进行4次重复催化实验中也能保持很高的催化活性。3.通过ATRP法合成分子量可控、分子量分布窄的P4VP-Cl，以P4VP-Cl为大分子引发剂引发甲基丙烯酸叔丁酯（tBMA）进行ATRP反应合成一系列不同链段比的嵌段共聚物P4VP-b-PtBMA，通过对P4VP-b-PtBMA的叔丁基定向水解，制备嵌段聚电解质P4VP-b-PMAA。研究P4VP-b-PMAA在不同pH值下的自组装行为。结果发现在pH=2的水溶液中，自组装形成以PMAA为核，P4VP为壳的胶束；在pH=10的水溶液中自组装形成以P4VP为核，PMAA为壳的胶束，通过¹H-NMR表征胶束的不同核-壳结构。进而研究了不同溶剂与链段比对P4VP-b-PMAA胶束化行为的影响。4.通过ATRP法合成分子量可控、分子量分布窄的聚甲基丙烯酸-N,N-二甲氨基乙酯（PDMAEMA）。深入研究了PDMAEMA的分子量、浓度和体系的pH值对PDMAEMA的LCST的影响。进而以PDMAEMA为大分子引发剂引发第二单体St在DMF溶液中进行ATRP反应合成一系列不同链段比的具有pH与温度双响应性的嵌段共聚物PDMAEMA-b-PSt。深入探讨了聚合物的链段比、浓度、温度及体系pH值对聚合物胶束化行为的影响，结果发现随着PSt链段的增加，胶束的LCST减小，粒径增加，Zeta电位减小；随着体系pH值的增加，胶束粒径减小，粒径分布变窄；随着浓度的增加，LCST减小；随着温度的增加，胶束粒径减小。通过TEM观测胶束PDMAEMA₁₅-b-PSt343的形态，发现在DMF溶剂中不同pH条件下PDMAEMA-b-PSt自组装形成球形、碗状、囊泡与串珠状的胶束，在1,4-二氧六环/H₂O（v/v=94/6）混和溶剂中形成大复合胶束。更多还原

【Abstract】 The living polymerization can be divided into living anionic polymerization, living cationicpolymerization and living free radical polymerization by different initiation modes. Livingfree radical polymerization has been extensively studied in recent years due to the mildreaction conditions and the widely applicable monomer. Living free radical polymerizationcontains initiator-transfer agent-terminator （iniferter）, nitroxide mediated polymerization（NMP） or stable free radical polymerization （SFRP）, and reversible addition fragmentationchain transfer （RAFT） radical polymerization and atom transfer radical polymerization（ATRP）. ATRP is widely available for the polymerization of many vinyl monomers due to thehigh reaction rate, the mild reaction temperature, a wide range of applicable monomers, andused to prepare the determinate structure of homopolymers, block/graft copolymer andorganic/inorganic hybrid materials.The morphology of amphiphilic copolymer assembly is influenced by many factors: suchas the chemical structure, molecular weight, the relative content of the segment, the sequenceof the segment and the nature of the solvent, etc. Due to the novel structure and uniqueproperties of the assembly, it is expected to have broad application prospects in medicine,green materials, bio-engineering, nano-materials, and medical diagnosis.Accordingly, this paper is mainly about the synthesis of different structure copolymers byATRP, the copolymerization reaction and the micellization behavior; the main contentsinclude the following aspects:1. The controlled number-average molecular weight and narrow distributionpoly（4-vinylpyridine） macromonomer （St-P4VP） with a styryl end group was synthesizedby ATRP of4-vinylpyridine using p-（chloromethyl）styrene （CMSt） as functional initiator.Poly（4-vinylpyridine） grafted polystyrene microspheres （P4VP-g-PSt） were then preparedby dispersion copolymerization of styrene with St-P4VP macromonomers. The effects ofpolymerization reaction parameters such as medium polarity, concentration of St-P4VPmacromonomer and polymerization temperature on the sizes and size distribution ofP4VP-g-PSt microspheres were investigated. P4VP distributed on the surface ofP4VP-g-PSt microspheres which made the microspheres had pH responsive.Ag/P4VP-g-PSt composite microspheres were synthesis by Ag nanoparticles stabilized onthe surface of the P4VP-g-PSt microspheres via the in situ reduction of Ag+, thecoordination interaction took place between the Ag+and pyridine group of P4VP. Thecatalytic performance and antibacterial property on Escherichia coli and Staphylococcusalbus of Ag/P4VP-g-PSt composite microspheres was studied.2. The controlled number-average molecular weight and narrow distribution star polystyrene,（PSt-Br）4, was firstly synthesized by ATRP of styrene （St） using pentaerythritol terakis（2-bromoisobutyrate）（4Bri-Bu） as four-armed initiator. Then,（PSt-b-PNIPAM）4wereprepared using （PSt-Br）4as macroinitiator. The self-assembly behaviors of theamphiphilic four-armed block copolymers （PSt-b-PNIPAM）4in mixed solution and thelower critical solution temperature （LCST） of the resulting micelles were investigated. The gold nanoparticles （Au NPs） were immobilized on the surfaces of the micelles by thereduction of the corresponding ions. The micelle-supported gold nanoparticles（Au-micelles） were applied to catalyze the reduction of p-nitrophenol. Moreover, theactivity of the Au-micelle catalyst could be modulated by the temperature and theAu-micelles could be easily recovered by changing the temperature and recycled fourtimes with high catalytic activity.3. The controlled the number-average molecular weight and narrow distributionpoly（4-vinylpyridine） with a chlorine end group （P4VP-Cl） was prepared by ATRP. Then,poly（4-vinylpyridine）-b-poly（tert-butylmethacrylate）（P4VP-b-PtBMA）, was synthesizedusing P4VP-Cl as macroinitiator by ATRP. Poly（4-vinylpyridine）-b-poly（methacrylic acid）（P4VP-b-PMAA） was obtained by hydrolyzing the P4VP-b-PtBMA copolymer underroom temperature. The self-assembly behavior of P4VP-b-PMAA copolymer was alsoinvestigated, the nanomicelles with PMAA core and P4VP corona were formed at low（acidic） pH, while nanomicelles with P4VP core and PMAA corona were formed at high（basic） pH. The morphology of P4VP-b-PMAA micelles was significantly affected bysolvent, segment ratio and pH.4. Macroinitiators poly（2-（dimethylamino）ethyl methacrylate）（PDMAEMA） weresynthesized by ATRP using ethyl-2-chloropropionate （ECP） as initiator. Then amphiphilicblock copolymers PDMAEMA-b-PSt with different segment ratio were synthesized byATRP using PDMAEMA-Cl as macroinitiator. The amphiphilic block copolymersPDMAEMA-b-PSt in selective solution could self-assemble to form micelles. pH,segment ratio and temperature which affected the diameter of the micelles wereinvestigated, the diameter and Zeta value increased with the increment of the hydrophobicchain length or the decrement of pH, and the diameter decreased with the increment of thetemperature. The micelles had pH and temperature dual responsive. The morphology ofmicelle PDMAEMA₁₅-b-PSt₃₄₃was observed by TEM, PDMAEMA-b-PSt self-assembledspherical, bowl, vesicles and beaded micelles, under different pH in DMF.PDMAEMA15-b-PSt343formed macrocomposite micelles in1,4-dioxane/H2O （v/v=94/6）mixed solvent.更多还原