Self-assembly and self-organisation in fluctuating systems of dipolar colloids: Towards a coarse-grained theoretical description

本计画主要研究平衡态与非平衡态自组胶体结构的动力学现象。在感兴趣的结构中，粒子之间的键不是化学性质的，而是由定向、偶极或多极相互作用产生的。因此，热涨落对弛豫动力学以及非平衡态的自组织起着重要作用。调查将进行适当的模型系统，没有明确的溶剂的计算机模拟的基础上。所考虑的特定模型受到胶体物理学的启发;然而，在波动存在下的自组装在各种生物学背景中也起着关键作用，例如蛋白质组装和微生物聚集。该项目的主要部分集中在系统跨越网络的形成和相应的松弛动力学平衡。在这里，我们将进行粒子分辨模拟，详细阐明平移和定向单粒子动力学。然而，主要的目标是构建一个粗粒度的，随机描述的动态的基础上减少连续的多粒子动力学到一个离散的状态集。对于感兴趣的自组装系统，这是一种创新的方法，我们期望从中更深入地了解弛豫时间和聚集过程的途径。此外，我们将扩展我们的研究到非平衡偶极系统的自组装（自组织），特别是涉及自推进机制的活性偶极粒子簇的形成。特别感兴趣的是取向波动和流体力学的作用。作为一个长期的目标，我们的目标也是发展粗粒度的战略（基于状态离散化），这样的非平衡系统。

This project is concerned with the investigation of dynamical phenomena in selfassembled colloidal structures in equilibrium and in nonequilibrium. In the structures of interest, bonds between particles are not of chemical nature, but arise from directional, dipolar or multipolar, interactions. As a consequence, thermal fluctuations play a major role for play a major role for the relaxation dynamics, as well as for the self-organization in nonequilibrium. The investigations will be carried out based on computer simulations of suitable model systems without explicit solvent. The specific models considered are inspired by colloidal physics; however, self-assembly in presence of fluctuations also plays a key role in various biological contexts, such as protein assembly and aggregation of microorganisms. The main part of the project focuses on the formation of system-spanning networks and the corresponding relaxation dynamics towards equilibrium. Here, we will perform particle-resolved simulations to elucidate in detail the translational and orientational single-particle dynamics. The major goal, however, is to construct a coarse-grained, stochastic description of the dynamics based on a reduction of the continuous many-particle dynamics into a discrete set of states. For the self-assembling systems of interest, this is an innovative approach from which we expect a deeper understanding concerning relaxation times and the pathways of the aggregation process. Further, we will extend our research to the self-assembly (selforganization) of nonequilibrium dipolar systems, particularly the formation of clusters of active dipolar particles which involve a self-propulsion mechanism. Of particular interest is the role of orientational fluctuations and hydrodynamics. As a long-term goal, we also aim at developing coarse-graining strategies (based on state discretization) for such nonequilibrium systems.