DMREF: Collaborative Research: Programming mesostructured colloidal soft matter through complex quenching and annealing

该项目支持综合实验、建模和模拟，以实现通过胶体材料的热加工来控制材料性能的新方法。其目标是开发具有温度敏感相互作用的新型胶体悬浮液，以及通过淬火、退火和回火可控制地将其加工成具有所需结构和机械性能的胶体固体的策略。这些新工具的开发和它们创造的知识可能会导致具有良好控制和新特性的胶体材料的变革性、新的和可扩展的加工方法，并可能影响一系列技术，包括人造组织支架、分离膜和用于添加剂制造的油墨。这项研究将与教育活动相结合，培训学生制作具有独特结构和性质的胶体固体的新方法。热处理长期以来一直被用于原子和分子材料，但在胶体材料中一直难以捉摸，因为缺乏易于控制的温度响应行为的胶体系统，以及缺乏对热历史如何影响这些系统中结构形态和特征的发展和停滞的基本了解。在这个项目中，将使用新开发的热响应性胶体以及大规模模拟和实验来克服这些挑战，这些模拟和实验可以快速探测从这些胶体中出现的多种可能的热历史和结构。实验和模拟将结合起来，以表征热力学变量中的运动轨迹如何映射到紧急结构相关性和材料特性(包括流变学)的相关描述符上。领先的努力将建立均匀流体相以及相共存的亚稳态(双节点)和不稳定(调幅节点)区域中的淬火的分类行为，随后将在这些区域中的一个以上区域进行更复杂的淬火，以寻找新的结构和流变学。这样做将使我们能够更基本地了解胶体流体中胶凝、相分离和玻璃形成的动力学过程是如何竞争来启动、演化并最终阻止结构的，以及阻止结构的特征如何控制材料的线性和非线性力学。这一基本认识将被用来开发一个新的概念性框架，利用热加工来设计和设计具有明确结构和性能的胶体材料。

The project supports integrated experiments, modeling and simulations to enable new ways of controlling material properties through thermal processing of colloidal materials. The goal is to develop new colloidal suspensions with temperature-sensitive interactions, and strategies by which they can be controllably processed into colloidal solids with desired structure and mechanical properties through quenching, annealing and tempering. The development of these new tools and the knowledge they create could lead to transformative new and scalable processing methods for colloidal materials with well-controlled and novel properties, and potentially impact a range of technologies including artificial tissue scaffolds, separation membranes, and inks for additive manufacturing. The research will be integrated with educational activities to train students in a new approach to making colloidal solids having unique structures and properties.Thermal processing has long been known and employed for atomic and molecular materials, but has been elusive in colloidal materials because of a lack of colloidal systems with easily controlled temperature-responsive behavior, as well as a dearth of fundamental understanding for how the thermal history influences the development and arrest of structural morphologies and features in these systems. In this project, these challenges will be overcome using newly developed thermoresponsive colloids, and large-scale simulations and experiments that can rapidly probe the multitude of possible thermal histories and structures that emerge from them. Experiments and simulation will be combined to characterize how kinetic trajectories in thermodynamic variables map onto the relevant descriptors of emergent structural correlations and material properties including rheology. Leading efforts will establish categorical behavior for quenches in the homogeneous fluid phase, as well as in both metastable (binodal) and unstable (spinodal) regions of phase coexistence, followed on by more complex quenches involving annealing in more than one of these regions to seek out novel structures and rheology. Doing so will enable a more fundamental understanding for how kinetic processes of gelation, phase separation and glass formation compete in colloidal fluids to initiate, evolve and eventually arrest structure, and how the features of the arrested structure control the linear and non-linear mechanics of the material. This fundamental understanding will be used to develop a new conceptual framework for using thermal processing to design and engineer colloidal materials with well-specified structure and properties.