线形ABC三嵌段共聚物自组装的耗散粒子动力学模拟研究

发布时间：2018-03-28 08:14

本文选题：耗散粒子动力学　切入点：线形ABC三嵌段共聚物　出处：《西南科技大学》2017年硕士论文

【摘要】：嵌段共聚物自组装能够形成大量有序的纳米结构,使其在药物传递、微电子材料、先进塑料等方面有潜在的应用前景。所以近年受到人们的广泛关注。由三种不同嵌段组成的线形ABC9(l-ABC)三嵌段共聚物具有拓扑结构简单的特点,继二嵌段共聚物之后成为新的研究热点。本文采用耗散粒子动力学模拟方法(DPD)研究线形l-ABC三嵌段共聚物在溶液、剪切和受限这三种条件下的自组装行为。1、研究l-ABC三嵌段共聚物通过溶液浓度诱导其自组装行为。首先,通过改变l-ABC的浓度、嵌段长度比例,首次发现了内部含有反向胶束的核-壳-冠(CSC)结构、六方堆积圆柱、环形结构、多室胶束等。所发现的反向CSC结构很好解释了实验观测误差的来源。其次,随着嵌段共聚物浓度增加,微观形貌从三维或二维向一维演化。最后,这些形貌动力学演化过程与星形ABC三嵌段共聚物的成核、合并、生长演化过程相似。界面张力对最终形貌的形成有重要的影响。2、引入稳态剪切条件研究了l-ABC的自组装行为。从315种结构中归纳出7种球形(0D),10种圆柱形和1种扁球形(1D),5种薄片和3种扁圆柱形(2D)胶束结构。当浓度φ00.1,剪切速率τ00.1时,l-BAC全部形成1D圆柱结构,lABC和l-BCA绝大多数形成1D圆柱结构。本文模拟得到的几种1D圆柱胶束结构具有形成单壁或双壁管以及圆柱混合胶束的潜力。最后,本文发现,通过调控剪切速率、嵌段共聚物浓度和亲溶剂嵌段长度等因素,可以产生0D、1D和2D纳米结构的重要因素。3、引入硬球受限空间探索l-ABC在受限诱导下的自组装行为。从210种模拟结构中得到几种全新的自组装结构,如多层洋葱、双螺旋、堆叠层状结构。当球形半径R060,嵌段间的相互作用参数为αB(25)αA(50)αC(120)时,对称嵌段B_2A_2C_2和B_2C_2A_2形成标准的核-壳-冠(CSC)纳米结构;当R060,αB 0αA 0αC 0120时,A_2B_2C_2和B_2C_2A_2形成层状结构,B_2A_2C_2形成螺旋结构。当半径增加到R080时,多层洋葱结构的层数随之增加。
[Abstract]:Self-assembly of block copolymers can form a large number of ordered nanostructures, enabling them to be used in drug delivery, microelectronic materials, Advanced plastics have potential applications in many fields, so they have been paid more and more attention in recent years. The linear ABC9- ABC3-block copolymers with three different block compositions have the characteristics of simple topological structure. Following diblock copolymers, diblock copolymers have become a new research hotspot. In this paper, the linear l-ABC triblock copolymers in solution were studied by means of dissipative particle dynamics simulation. The self-assembly behavior of l-ABC triblock copolymers induced by solution concentration was studied. Firstly, by changing the concentration of l-ABC, the ratio of block length to block length was changed. For the first time, the core-shell-crown CSC structure containing reverse micelles, hexagonal stacked cylinder, annular structure, multi-compartment micelle and so on has been found for the first time. The source of the experimental observation error is well explained by the reverse CSC structure. With increasing the concentration of block copolymers, the micromorphology evolves from three to two dimensions to one dimension. Finally, the kinetic evolution of these morphologies is combined with the nucleation of star ABC triblock copolymers. The process of growth and evolution is similar. The interfacial tension has an important effect on the formation of final morphology. 2. The self-assembly behavior of l-ABC is studied by introducing the steady state shear condition. From the 315kinds of structures, 7 kinds of spherical 0DX and 10 kinds of cylinders and 1 kind of flat sphere are concluded. There are 5 kinds of thin sheet and 3 kinds of flat cylinder shape 2D) micelle structure. When the concentration is 蠁 0. 1, shear rate 蟿 0. 1 l BAC forms 1D cylindrical structure. Most of them form 1D cylindrical structure. Some 1D cylindrical micelle structures obtained in this paper have been obtained by simulation. Have the potential to form single-walled or double-walled tubes and cylindrical mixed micelles. Finally, It is found that by regulating the shear rate, the concentration of block copolymers and the block length of hydrophilic solvent, and so on, The important factor that can produce the 0D1D and 2D nanostructures. 3, the hard sphere confined space is introduced to explore the self-assembly behavior of l-ABC induced by restriction. Several new self-assembled structures, such as multilayer onion, double helix, are obtained from 210 simulated structures. Stacked layered structure. When the spherical radius R060 and the interaction parameter between the blocks are 伪 B ~ (25) 伪 A ~ (50) 伪 C ~ (2 +)), the symmetric block B_2A_2C_2 and B_2C_2A_2 form the standard core-shell (CSC-C) nanostructure. When R060, 伪 B0 伪 A0 伪 C 0120, the number of layers in the multilayer onion structure increases when the number of layers in the multilayer onion structure increases with the increase of the radius of R060, 伪 B0 伪 A0 伪 C 0120, and the B_2C_2A_2 cambium structure, the number of layers of the multilayer onion structure increases as the radius increases to R080.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631.1

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