【作者】 李洋；

【导师】 吕中元；

【作者基本信息】 吉林大学 ， 物理化学， 2014， 博士

【摘要】 各向异性的补丁粒子是由一个以上具有不同形状、位置、化学功能以及光、电、磁和力学特性的区域构成的纳米粒子或者胶体粒子。由于不同区域间的特殊相互作用，它们通常可以自组装形成有序结构，而这些有序结构具有很多潜在的应用，例如光子晶体、药物输运、数据存储以及条码技术等。为了更好的应用补丁粒子形成的组装结构，深入理解补丁粒子的自组装过程是十分必要的。因此本文布朗动动力学（Brownian Dynamics，BD）模拟方法研究了典型三嵌段补丁粒子的自组装行为，明确了两类补丁粒子自组装结构的调控规律。我们通过布朗动力学方法研究了具有对称性的双补丁粒子ABA在稀溶液中的自组装行为，其中A为补丁粒子的两极，B为补丁粒子的赤道。通过深入分析具有不同表面覆盖面积的双补丁粒子在选择性溶剂中的自组装过程，我们发现当选择性溶剂对粒子的补丁部分为不良溶剂，但是对于非补丁部分却为良溶剂时，在补丁尺寸较小的情况下可以得到线状结构，在补丁尺寸较大的情况下可以得到三维网络结构。当选择性溶剂对粒子的补丁部分为良溶剂，但是对于非补丁部分却为不良溶剂时，在补丁尺寸较大的时候可以得到层状结构，在补丁尺寸较小的时候只能得到聚集体结构。自组装是组装基元通过弱相互作用自发地形成有序结构的过程，多级自组装则提供了更加精确的控制手段，还可以对有序结构进行二次优化。近年来，多级自组装方法在具有优异性能的多肽、嵌段共聚物、纳米粒子和胶体粒子组装中备受关注。我们利用布朗动力学方法系统研究了ACB三嵌段补丁粒子的多级自组装过程，即将第一级组装得到的产物作为第二级组装的初始构型。多级自组装为制备具有复杂功能的结构提供了高效可行的方案，我们的模型更进一步，可以精确调控补丁的大小。第一阶段的组装在较低浓度、只有A-A疏水相互作用情况下进行，得到的产物为第二级组装提供反应物。在第二个阶段允许B-B疏水相互作用，我们通过退火的方法研究了第二级组装从反应物到目标结构的过程，并且讨论了浓度和吸引强度的影响。我们主要通过调控体系中补丁B部分的吸引强度和补丁粒子的浓度，研究了第二级组装过程中形成有序结构的影响因素。通过合理的设计组装模型、组装规则和组装路线，最终得到了蜂巢状网络结构和金刚石状结构。结果表明补丁B部分在较高的吸引强度和适当的浓度下，可以得到更多并且更规整的蜂巢状结构。而对于金刚石状结构，较高和较低的吸引强度和浓度都不利于其形成。更多还原

【Abstract】 Patchy particles usually consist of more than one different regions withdiverse shapes, positions, chemical functionalities and electrical properties. Dueto specific interactions between different pattens, they often self-assemble intoordered structures which have numerous potential applications in many fields,such as photonic crystals, drug delivery, date storage and barcoding. In order tomake the self-assembly structures of patchy particles have a better application, itis necessary to understand the self-assembly process of patchy particles. In thisstudy, Brownian dynamics simulation method has been used to investigate theself-assembly behavior of ABA and ACB triblock patchy particles.We study the self-assembly behavior of two-patch particles with D∞hsymmetry by using Brownian dynamics simulations. The self-assemblyprocesses of two-patch particles with diverse patch coverage in two selectivesolvent conditions are investigated. The patchy particles form linear thread-likestructures with low patch coverage in a solvent that is bad for patches but goodfor matrix, whereas they form three-dimensional network structures withrelatively high patch coverage on surface. For patchy particles in a solvent thatis good for patches but bad for matrix, monolayer structures are obtained at highpatch coverage, and only cluster structures emerge when surface patch coverageis low.Hierarchical self-assembly provides a more precise control to optimizeordered structure quadratically. In recent years, the hierarchical self-assemblymethods are used to study the complex stuctures and excellent propertiesderived from the polypeptide, block copolymer, nanoparticles and colloidalparticles. We investigate the hierarchical self-assembly of ACB triblock patchyparticles, where the self-assembly product of first stage is set as the initialstructure for the second stage self-assembly. Hierarchical assembly offers apromising route that allows to fabricate a range of functional structures, the size of the patch can be precisely regulated in our models. In the first stageself-assembly，we only allow A-A hydrophobic attraction at low concentrationto refine self-assembly subunits for next stage.In the second stage, B-B hydrophobic attraction is also allowed to generatethe the second stage self-assembly structures. By regulation the interactionbetween patch B as well as the concentration of patchy particles, the factors thatinfluence the ordered structures are studied. Via properly designing theassembly models, routes and rules, we can observe the formation of honeycombnetwork structure and diamond structures, respectively. The results reveal thatthe strong attraction between patch B is good for honeycomb network structureformation in solution with suitable patchy particle concentrations. But it isnecessary to choose appropriate attraction between patch B and theconcentration to get the diamond structures.更多还原