介观非球形胶体粒子自组装动力学模拟研究

Nanoparticle is the assembly element of substances at mesoscopic scale. The self-assembly behaviour of nonspherical colloidal particles is closely related with the shapes and structures of these particles. In this project, a framework to simulate the dynamics of the self-assembly of nonspherical particles with arbitrary shapes is proposed based on the tabulated potential method. The tabulated potential is extracted with a simple potential function by fitting the original potential of nonspherical particle consisting of all atoms. The force and moment between particles is calculated using the numerical technologies. Finally, the self-assembly dynamics is built according to the conventional theory of rigid body dynamics and the stochastic dynamics simulation is realized. The potential energy surfaces for two nonspherical particles and metastable conformations are systematically analyzed. Applying present simulation framework, the self-assemblies of nonspherical particles (Janus and Patchy colloidal particles, polyhedral particles, protein crystallization, capsid proteins) are studied. The influences of particle concentration, temperature and particle structure on the final self-assembled structures are explored and further compared with the experimental results. It is valuable to guide the design of novel mesoscopic self-assemblies of nonspherical particles.

纳米粒子是物质在介观尺度下的组装基元，非球形胶体粒子自组装行为与胶体粒子的具体形貌和结构密切相关。本项目拟采用作用势参数列表法构建可以描述任意形貌和结构的非球形粒子自组装动力学模拟架构，该方法从全原子目标对象出发，直接计算介观粒子间作用势，再通过目标势场进行函数拟合，获取函数参数并列表，最后采用数值方法计算非球形粒子间受力和力矩，根据刚体分子动力学构建非球形粒子随机动力学模拟架构；系统分析非球形结构粒子间的作用势能面和亚稳态粒子对构象；采用该模拟架构系统研究非球形粒子（Janus和Patchy粒子、多面体粒子、蛋白质结晶、壳蛋白）自组装规律，包括粒子浓度、温度和粒子结构对自组装结构的影响，并同实验结果定量比较，为设计新颖介观粒子自组装结构提供指导。

非球形胶体粒子的自组装行为与粒子形貌和结构密切相关，通过计算机模拟深入认识组装粒子形貌与组分分布对粒子自组装规律的影响，对自组装设计有着重要的学术价值。在该项目中，我们基于参数列表法构建了能够定量描述轴对称粒子或非轴对称粒子形貌的力场方法和对应的粒子布朗动力学模拟架构，从而实现了对任意粒子形貌的描述和自组装动力学模拟。我们采用非球形粒子模拟架构系统研究了Janus椭球、圆锥形、截断圆锥形粒子、圆环、碗型粒子、截角立方体和截角八面体自组装规律，获得了非球形粒子自组装相图并对其自组装机理进行了深入分析。为了进一步认识和验证粒子形貌对其组装行为的影响，我们采用微流控技术制备了尺寸及形貌均一的Janus胶体粒子和碗状胶体粒子，并对碗形粒子的自组装行为进行了深入研究，探索了椭球形Janus高分子胶体粒子的制备方法，这些模拟和实验研究结果为认识和设计新型非球形粒子及自组装调控提供有价值的信息和指导。