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。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、退火和回火将其可控地加工成具有所需结构和机械性能的胶体固体的策略。这些新工具的发展及其创造的知识可能会导致具有良好控制和新颖特性的胶体材料的变革性和可扩展的新处理方法，并可能影响一系列技术，包括人工组织支架，分离膜和用于增材制造的油墨。该研究将与教育活动相结合，以训练学生用一种新的方法来制造具有独特结构和性质的胶体固体。热加工早已为原子和分子材料所知并应用，但由于缺乏易于控制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捕获的基本理解，在胶体材料中一直难以捉摸。在这个项目中，这些挑战将通过新开发的热响应胶体，以及大规模的模拟和实验来克服，这些模拟和实验可以快速探测从中产生的大量可能的热历史和结构。将结合实验和模拟来描述热力学变量中的动力学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。主要的努力将建立在均匀流体相中淬火的分类行为，以及在相共存的亚稳（双节点）和不稳定（spinodal）区域，随后是更复杂的淬火，包括在多个这些区域退火，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凝、相分离和玻璃形成的动力学过程如何在胶体流体中相互竞争，以启动、发展和最终捕获结构，以及捕获结构的特征如何控制材料的线性和非线性力学。这种基本的理解将用于开发一个新的概念框架，用于使用热加工来设计和工程具有良好规定的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.