通过层层自组装制备聚电解质自修复微胶囊

发布时间：2018-03-31 19:25

本文选题：层层自组装法　切入点：聚电解质微胶囊　出处：《深圳大学》2017年硕士论文

【摘要】：两种荷异种电荷的聚电解质之间存在库仑引力,利用这个性质可以让它们通过交替的层层自组装方式形成微胶囊,这种微胶囊具有离子敏感的特性,可以被多种离子所触发,释放内容物,在生物医药领域备受关注,可用于人体的靶向给药或者定向组织移植。本文针对混凝土中的氯害和碳酸化这两个严重影响混凝土耐久性的重大工程问题,提出了将这种具有离子响应特性的通过层层自组装法制备的聚电解质微胶囊加入到混凝土中,为混凝土建立一个抗有害离子入侵的免疫系统,以实现混凝土的化学自修复。用于生物体的聚电解质微胶囊不能直接包裹芯材,通常在制备时是以固体微球作为模板,进行聚电解质层层自组装后再溶去模板,注入液体的芯材,同时,所制得的微胶囊也只能存在于水相中。一旦除去连续的水相,微胶囊将会溃散。为了使这种微胶囊适用于混凝土,本文对聚电解质层层自组装法制备微胶囊的工艺进行了改进,实现了:(1)在流动的环氧液滴表面直接包覆聚电解质,形成微胶囊;(2)通过聚电解质层间的交联稳定微胶囊的壳层结构,使聚电解质微胶囊可以在混凝土的无水环境下稳定存在。此外,为了提高包覆效率,适应混凝土应用的“量大价廉”的要求,本文还采用了可聚合乳化剂,在液体芯材表面进行光聚合,先形成一荷电网状稳定层,再进行聚电解质层层自组装,这种方法可以克服微胶囊形成初期聚电解质层数很低时,在高速离心过程中的破裂问题,大大提高了微胶囊化的效率。实验递进地分为三个部分,分别是:(1)传统的模板法制备环氧微胶囊:在CaCO_3沉积时,加入PSS调控CaCO_3结晶形态。当PSS的浓度为5 mg/mL时制得良好的球形微粒,平均粒径为8.6±0.6μm,比表面积约为8.8±0.5 m2/g,表面电位-45 mV左右。以此CaCO_3微球为模板,在其表面上离子型聚电解质PAH和PSS的交替自组装,达到预定层数后除去碳酸钙模板,得到中空微胶囊(PSS/PAH)n,向里面包埋脂环族环氧T8210后,浸入戊二醛溶液对壁材进行交联,得到环氧/聚电解质微胶囊;(2)铵基阳离子型表面活性剂乳化液体芯材,然后聚电解质层层自组装直接包覆:用阳离子型表面活性剂双十二烷基二甲基溴化铵乳化十二烷,其铵基阳离子油性大于水性,固基本溶于油相十二烷,在十二烷液滴的表面铺展,使乳液荷正电并使其稳定,然后在乳液液滴表面上进行PSS和PAH的交替层层自组装,达到预定层数后,用戊二醛对壁材进行交联,得到十二烷/聚电解质微胶囊;(3)UV界面聚合法在液体环氧乳液液滴的表面上形成荷负电的网状聚合物膜,然后聚电解质层层自组装制备液态环氧微胶囊:环氧是很好的混凝土修复剂。将环氧E44与可聚合的表面活性剂,不饱和酯环氧丙烯酸酯、丙烯酰胺、和甲基丙烯酸羟丙磺酸钠混合,乳化后在液滴表面进行UV聚合,形成一层荷负电的网状薄膜。这层膜既能保护芯材在低速搅拌时不流失,也不影响后面的触发效果,在薄膜基础上组装聚电解质至预定层数,再进行壁材的交联,得到易于保存且稳定的环氧/聚电解质微胶囊。实验表明,利用戊二醛(GA)对囊壁中的PAH组分进行交联,生成一种吡啶结构,使囊壁形成类似于互穿聚合物的网络结构,可以稳定整个多层膜,既能很好地加固微胶囊的稳定性,也不影响胶囊对离子的响应。三种方法制备的聚电解质微胶囊都能在PH≥12的碱性溶液中触发,释放液体芯材。本论文通过制备方法的不断改进,在模板法的基础上完成了聚电解质在液体芯材上的直接包覆,简化了制备流程,拓宽了聚电解质微胶囊的应用范围。通过采用戊二醛对聚电解质壁材中PAH的交联,成功制备出了可以在无水状态下稳定存在的聚电解质自修复微胶囊干粉,在重新注水后未失去对离子的响应特性。采用可聚合表面活性剂,在液体表面预先形成单分子厚度的稳定壳层,使乳液液滴在高速离心过程中不破碎,不合并,可以大大提高聚电解质包覆液体芯材的效率。总之,本文的实验表明,通过层层自组装制备的聚电解质微胶囊可以用于混凝土,通过离子自动触发,实行混凝土的化学自修复。
[Abstract]:There are two kinds of heterogeneous charge Coulomb attraction between charged polyelectrolytes, may make use of this property to let them through the alternate layer by layer self-assembly to form microcapsules, the micro capsule has the characteristics of ion sensitive, can be triggered by various ions, releasing the contents, has attracted much attention in the field of biological medicine, can be used for human targeting the medicine or directional tissue transplantation. Aiming at the concrete carbonation and chloride and the two major engineering problems seriously affect the durability of concrete, put forward the ion response characteristics through layers of self-assembly of polyelectrolyte microcapsules prepared by adding into concrete, establish an anti immune intrusion of harmful ions in order to realize the system for concrete, concrete chemical self repair. For the biological polyelectrolyte microcapsules can not directly coated core material, usually at the time of preparation is a solid micro The ball as a template for polyelectrolyte layer by layer self-assembly after dissolving the template into the liquid core material, at the same time, microcapsules can only exist in the water phase. Once removed continuous aqueous phase, micro capsule will be scattered. In order to make this kind of microcapsule is suitable for concrete, preparation of microcapsules in this paper the polyelectrolyte layer by layer self-assembly method was improved and realized: (1) on the surface of epoxy droplet flow directly coated polyelectrolyte microcapsules are formed; (2) the shell structure of poly electrolyte layer between the crosslinked stable microcapsules, the polyelectrolyte microcapsules can exist stably in the anhydrous environment of concrete the next. In addition, in order to improve the coating efficiency, adapt to the concrete application of the "large quantity of cheap" requirement, this paper uses the emulsifier for photo polymerization in liquid core material surface, forming a grid shaped charge stable layer, and then poly electric The quality of the solution self-assembly, this method can overcome the early formation of polyelectrolyte microcapsules layers are low, fracture problems in high-speed centrifugal process, greatly improving the efficiency of microencapsulation. The order is divided into three parts, namely: (1) the traditional template preparation of microcapsules in epoxy the deposition of CaCO_3, adding PSS regulation of CaCO_3 crystal morphology. When PSS concentration was 5 mg/mL for spherical particles with good, average particle size is 8.6 + 0.6 m, about 8.8 + 0.5 m2/g specific surface area, surface potential of -45 mV. This CaCO_3 microspheres on the surface of ion type polyelectrolyte PAH and PSS self-assembly, calcium carbonate template removal reaches a predetermined number, get the hollow capsules (PSS/PAH n), to which the embedding of alicyclic epoxy T8210, the wall material is immersed in glutaraldehyde crosslinking, epoxy / polyelectrolyte microcapsules; (2) ammonium cation Ionic surfactant emulsion liquid core material, then the polyelectrolyte layer by layer self-assembly coated directly with cationic surfactant dodecyl bromide emulsion two methyl twelve alkyl ammonium cations, the oil than water, solid basic oil soluble phase twelve alkanes, twelve alkane droplet spreading on the surface, the a positively charged emulsion and make it stable, then in alternating emulsion droplets on the surface of PSS and PAH layers of self-assembly, reaches a predetermined number after crosslinking for wall material with glutaraldehyde, twelve alkane / polyelectrolyte microcapsules; (3) reticular polymer film UV interface polymerization on the surface of liquid epoxy emulsion droplets on the formation of negatively charged polyelectrolyte layers, then prepared by the self-assembly of liquid epoxy microcapsules: epoxy concrete repairing agent is good. The epoxy E44 and a polymerizable surfactant, unsaturated ester epoxy acrylate, acrylamide, Mixed with methyl acrylic acid hydroxypropyl sodium sulfonate, emulsified in droplet surface UV polymerization, forming a layer of negatively charged mesh film. This film can protect the core material loss at low speed, also does not affect the triggering effect, to set pre assembled polyelectrolyte layers in thin films based on cross-linked again for the wall material, are easy to preserve and stable epoxy / polyelectrolyte microcapsules. Experiments show that using glutaraldehyde (GA) of PAH group in the cyst wall was crosslinked to generate a pyridine structure, the cystic wall similar to the formation of interpenetrating polymer network structure, which can stabilize the whole multilayer film. Good to reinforce the stability of the microcapsule, does not affect the response of capsule ions. Three kinds of preparation methods of microcapsules can trigger in alkaline solution PH = 12, the release of liquid core material. Through preparation methods of this paper are improved in mold Based on the method of plate to complete the direct coating of polyelectrolytes in liquid core materials, simplifies the preparation process, broaden the scope of application of polyelectrolyte microcapsules. By using glutaraldehyde on polyelectrolyte wall material of PAH crosslinking, successfully prepared can exist stably in the anhydrous state of polyelectrolyte self repair the micro capsule powder in water after re not lost on response of ions. The polymerizable surfactant, on the surface of the liquid in advance to form a stable shell thickness of a single molecule, the emulsion droplets in high speed centrifugal process is not broken, do not merge, can greatly improve the efficiency of polyelectrolyte coated liquid core material. In a word, the experiments in this paper show that through the layers prepared by the self-assembly of polyelectrolyte microcapsules can be used in concrete, automatically triggered by the ion chemistry to implement concrete self repair.

【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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