RAFT分散聚合诱导自组装制备纳米材料及应用

发布时间：2018-06-01 07:21

本文选题：RAFT + 聚合　；参考：《中国科学技术大学》2017年博士论文

【摘要】：聚合诱导自组装与再组织(PISR)方法可以在一锅中完成嵌段聚合物的合成、自组装,高效地制备聚合物纳米材料,近年来吸引了研究者的广泛关注。PISR的机理以及PISR过程中影响聚集体形貌和形貌转变的因素已经有了较为详细的报道,但是对PISR体系的拓展和应用仍需要进一步的研究。本论文利用PISR方法通过RAFT分散聚合制备多种形貌的聚合物纳米材料。通过加入共聚合单体改善了经典醇相苯乙烯聚合体系中单体转化率低、形貌转变困难的问题;将PISR法与光控活性聚合相结合,实现室温下制备聚合物纳米材料;利用PISR可以高效制备聚合物纳米材料的优势,制备硅纳米管载体材料,用于载药研究。取得的主要研究成果如下:1.通过在硅纳米管(SNT)表面接枝pH敏感性的聚合物,构建了一种新型的药物载体。利用PISR方法可以大量制备聚合物纳米棒,用聚合物纳米棒作为模板,在其表面沉积二氧化硅形成硅/聚合物杂化纳米棒,煅烧后得到空心的硅纳米管。用RAFT试剂对SNT进行修饰后,通过表面RAFT聚合得到两嵌段聚合物PDEAEMA-b-POEGMA修饰的硅纳米管(SNT-PDEAEMA-b-POEGMA)。阿霉素(DOX)被包载进入 SNT-PDEAEMA-b-POEGMA中,通过调节溶液的pH值可以实现药物的可控释放。细胞毒性及内吞实验结果显示这种纳米载体具有良好的生物相容性,能够有效地被细胞内吞,在药物和基因的传递领域具有潜在应用价值。2.使用PHEA作为大分子链转移剂,在甲醇中进行St和MMA的RAFT分散共聚合。与甲醇中St的分散聚合相比,St和MMA的RAFT分散共聚合可以促进嵌段聚合物纳米材料的形貌转变。通过改变St/MMA的摩尔比,我们绘制了三个相图来反映P(St-co-MMA)的聚合度、体系固含量和所得纳米材料形貌之间的关系,发现St/MMA的摩尔比也会对相图产生影响。使用超灵敏差示扫描量热法(US-DSC)测定甲醇分散液中聚合物纳米材料的玻璃化转变温度(Tg)。结果表明,甲醇中聚苯乙烯的Tg值随着共聚物中MMA结构单元摩尔含量的增加而降低。将MMA结构单元引入到聚苯乙烯链段中可以增强链段的活动能力,这有利于嵌段聚合物纳米材料发生形貌转变。3.以PDMAEMA作为大分子链转移剂,可见光控制下,在乙醇中进行了 BzMA的RAFT分散聚合,制备了多种形貌的聚合物纳米材料。与热引发的PISR体系不同,光控PISR可以在可见光以及室温下进行,条件更温和。我们使用了有机光催化剂通过光诱导电子能量(PET)转移过程来控制聚合的进行。聚合反应受光催化剂浓度和光源强度的影响。光源的"开/关"实验也证实了光源对聚合反应的控制能力。4.以PHEA作为大分子链转移剂,在甲醇中进行St和NMAS的RAFT分散共聚合反应。我们与相同条件下St的分散聚合反应进行了对比研究,发现少量NMAS单体(10%)与苯乙烯共聚合后,聚合体系的反应速率加快,同时促进了嵌段聚合物纳米材料形貌的转化,可以观察到胶束、纳米线以及囊泡。纳米线向囊泡转变的过程中出现了层状、水母状中间态形貌。通过改变聚合体系的固含量以及P(St-co-NMAS)的聚合度制备了一系列聚合物纳米材料,并根据其形貌绘制了相图,为大量、重复制备需要的聚合物纳米材料提供了依据。
[Abstract]:The polymerization induced self-assembly and re tissue (PISR) method can complete the synthesis of block polymers in one pot, self-assembled and highly efficient preparation of polymer nanomaterials. In recent years, the mechanism of extensive attention on.PISR and the factors affecting the transformation of aggregates and morphology in the PISR process have been reported in detail. Further research on the development and application of the PISR system is still needed. This paper uses the PISR method to prepare a variety of polymer nanomaterials by RAFT dispersion polymerization. By adding copolymerization monomers, the problems of low monomer conversion and difficult morphologies in the classical alcohol styrene polymerization system are improved, and the PISR method and the light controlled activity polymerization are used. The polymer nanomaterials are prepared at room temperature, and the advantages of polymer nanomaterials can be prepared by PISR, and silicon nanotube carrier materials are prepared. The main research results are as follows: 1. a new drug carrier was constructed by grafting pH sensitive polymers on the surface of silicon nanotube (SNT). A large number of polymer nanorods can be prepared by PISR method, and the polymer nanorods are used as templates to form silicon / polymer hybrid nanorods on the surface of the nanorods, and the hollow silicon nanotubes are obtained after calcining. After modifying the SNT with the RAFT reagent, the two block polymers modified by PDEAEMA-b-POEGMA are obtained by the surface RAFT polymerization. The nanotube (SNT-PDEAEMA-b-POEGMA). Adriamycin (DOX) is loaded into SNT-PDEAEMA-b-POEGMA and can be controlled by regulating the pH value of the solution. Cytotoxicity and endocytosis experimental results show that the nanoscale has good biocompatibility, can be endocytic effectively by the cell, in the field of drug and gene delivery. The potential application value.2. uses PHEA as a macromolecule chain transfer agent, RAFT dispersion copolymerization of St and MMA in methanol. Compared with the dispersion polymerization of St in methanol, RAFT dispersion copolymerization of St and MMA can promote the morphologies of block polymer nanomaterials. By changing the molar ratio of St/ MMA, we draw three phase diagrams to reverse the molar ratio of St/ MMA. The relationship between the degree of polymerization of P (St-co-MMA), the solid content of the system and the morphology of the obtained nanomaterials showed that the molar ratio of St/MMA would also affect the phase diagram. The glass transition temperature (Tg) of the polymer nanomaterials in the methanol dispersion solution (Tg) was determined by the ultra sensitive differential scanning calorimetry (US-DSC). The results showed that the Tg value of polystyrene in methanol was found. With the increase of the molar content of the MMA structural unit in the copolymer, the MMA structure unit is introduced into the polystyrene chain to enhance the activity of the chain segment, which is beneficial to the morphologies of the block polymer nanomaterials and the PDMAEMA as the macromolecule chain transfer agent. Under visible light control, the RAFT fraction of BzMA in the ethanol is carried out in the ethanol. A variety of polymer nanomaterials are prepared by dispersion polymerization. Unlike the heat induced PISR system, the photocontrolled PISR can be carried out at visible light and room temperature, and the conditions are more mild. We use organic photocatalyst to control polymerization through the light induced electron energy (PET) transfer process. The polymerization reaction is controlled by the concentration of photocatalyst and the light source. The "open / close" experiment of the light source also confirmed the control ability of the light source for the polymerization reaction.4. with PHEA as a macromolecule chain transfer agent and RAFT dispersion copolymerization of St and NMAS in methanol. We compared the dispersion polymerization of St with the same conditions, and found that a small amount of NMAS monomer (10%) was copolymerized with styrene. At the same time, the reaction rate of the polymerization system is accelerated and the transformation of the nanomaterial morphology is promoted. The micelles, nanowires and vesicles can be observed. In the process of the transformation of the nanowires to the vesicles, the formation of the nanowires, the jellyfish intermediate morphology, is prepared by changing the solid content of the polymerization system and the degree of polymerization of the P (St-co-NMAS). According to the morphology of the polymer nanomaterials, the phase diagrams are drawn, which provides a basis for the large number of polymer nanomaterials to be prepared repeatedly.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TQ316.322;TB383.1

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