基于微流控技术的荧光微胶囊制备以及梯度共聚物自组装

发布时间：2018-09-01 05:42

【摘要】：微流控技术是处理或操控微量流体的一种新型技术,它在化学、生物、医学等领域已经有广泛的应用。近年来,制作工艺简单、成本低的毛细管微流控装置在微胶囊的制备、微凝胶的构筑、聚合物自组装等领域具有越来越重要的应用价值。本论文通过设计具有特定结构的毛细管微流控装置,利用微流控技术重点开展了以下两方面的研究工作。一方面,设计了一种可实现气-液剪切的毛细管微流控装置,并通过气-液微流控技术制备了CdS量子点/壳聚糖复合微胶囊。量子点被包覆在微胶囊的液体腔中,并保持其良好的荧光特性。通过三维显微镜分析微流控参数对微胶囊粒径及分布的影响,采用显微镜研究了荧光微胶囊对不同环糊精(CD)溶液的响应性,并结合扫描电镜对微胶囊囊壁分析,分析了响应性产生的原因。研究结果表明,微胶囊的粒径随着气体流速的增大而变小但仍保持单分散性,液体流速对微胶囊的粒径影响不大。α-CD会使Cd S量子点/壳聚糖复合微胶囊表面变的粗糙、出现裂缝、甚至塌陷。更有趣的是,荧光微胶囊在α-CD溶液中会出现荧光的衰减,且α-CD溶液浓度越大荧光衰减的越明显。而β-CD却不会引起微胶囊表面形态和荧光强度发生变化。另一方面,设计了一种可实现同轴流体模型的毛细管微流控装置,并采用液-液微流方法进行梯度共聚物自组装的研究。先通过RAFT无皂乳液聚合的方法合成丙烯酸/甲基丙烯酸三氟乙酯(AA-TFEMA)梯度共聚物,利用核磁、DSC等表征了共聚物链的梯度结构。在微流控装置中对AA-TFEMA梯度共聚物进行自组装,详细探究了外相流速、内外相总流速、外相溶液、聚合物浓度对自组装聚集体形态的影响。结果表明,在微流控装置中,共聚物容易形成具有多种形态的聚集体,如球形和非球形的胶束。增大外相流速,非球形胶束的比例会增加。总流速减小后,微流控自组装不易进行。随着外相溶液中水含量减小,非球形胶束逐渐消失,而形成单一的球形胶束。共聚物浓度增大,会使自组装结构出现由球形向棒状向囊泡的转变。
[Abstract]:Microfluidic technology is a new technology for handling or manipulating trace fluids. It has been widely used in chemical, biological, medical and other fields. In recent years, capillary microfluidic devices with simple fabrication process and low cost have become more and more important in the preparation of microcapsules, the construction of microgels and the self-assembly of polymers. In this paper, a capillary microfluidic device with a specific structure is designed, and the following two aspects of research work are focused on by using the microfluidic technique. On the one hand, a capillary microfluidic device was designed to realize gas-liquid shear, and CdS quantum dot / chitosan composite microcapsules were prepared by gas-liquid microfluidic technique. Quantum dots are encapsulated in the liquid cavity of microcapsules and have good fluorescence properties. The effects of microfluidic parameters on the particle size and distribution of microcapsules were analyzed by three dimensional microscope. The response of fluorescent microcapsules to different cyclodextrin (CD) solutions was studied by microscope, and the wall of microcapsules was analyzed by scanning electron microscope (SEM). The causes of responsivity are analyzed. The results showed that the particle size of microcapsules decreased with the increase of gas flow rate, but remained monodispersity, and the flow rate of liquid had little effect on the particle size of microcapsules. 伪 -CD would make the surface of Cd S quantum dots / chitosan composite microcapsules rougher. Cracks appear, even collapse. What is more interesting is that fluorescent microcapsules show fluorescence decay in 伪 -CD solution, and the larger the concentration of 伪 -CD solution is, the more obvious the fluorescence decay is. However, 尾-CD did not change the surface morphology and fluorescence intensity of microcapsules. On the other hand, a capillary microfluidic device which can realize the coaxial fluid model is designed, and the self-assembly of gradient copolymers is studied by liquid-liquid microflow method. The gradient copolymer of acrylic acid / trifluoroethyl methacrylate (AA-TFEMA) was synthesized by RAFT soap-free emulsion polymerization. The gradient structure of the copolymer chain was characterized by NMR. The AA-TFEMA gradient copolymers were self-assembled in a microfluidic device. The effects of the flow rate of external phase, the total flow rate of internal and external phase, the solution of external phase and the concentration of polymer on the morphology of self-assembled aggregates were investigated in detail. The results show that the copolymers are easy to form aggregates with many forms, such as spherical and non-spherical micelles in microfluidic devices. The ratio of the non-spherical micelles will increase with the increase of the flow velocity of the external phase. The microfluidic self-assembly is not easy to carry out when the total flow velocity decreases. With the decrease of water content in the external phase solution, the non-spherical micelles gradually disappeared and formed a single spherical micelle. When the concentration of copolymer increases, the self-assembled structure changes from sphere to rod to vesicle.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;O631.1

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