Coarse Grained Modeling & Control of Colloidal Assembly

提出的项目的目标是开发不同形状的胶体颗粒集合的计算模型，作为控制其组装成有序的微结构的一种手段，几乎没有缺陷。提出的研究可能使超材料应用包括微结构胶体基材料的电磁辐射操纵。示例材料包括新型反射器、光栅、偏振器、波导等，作为传感器、太阳能电池、天线、光学计算机和隐形设备的一部分，它们都需要具有低缺陷密度的不同形状颗粒的周期性结构。该研究项目的重点将放在椭球和超椭球粒子的建模和控制上，以实现丰富的微观结构。使用方向和时变输入来控制相互作用的新方法将被开发，以实现胶体粒子组装过程的精确控制。了解胶体系统中的热力学和动力学具有挑战性，应用反馈控制为此类系统中的复杂响应工程增加了额外的一层。本研究的目标是建立最小的有物理意义的随机动力学模型，为椭球和超椭球粒子的装配设计基于模型的反馈控制策略。目标是显著地适应和扩展先前的方法，以系统地定义捕获结构特征的粗粒度系统坐标，同时消除系统对称性。反馈控制策略将通过可调的kt尺度相互作用进行实验测试，以设计不同形状粒子的动态可逆组装成有序的超材料。对胶体组装的设计规则和控制参数的基本理解将提供超越从试错发现中已知的新的一般见解。该项目将通过整合胶体科学、流体动力学、材料化学、高级计量/微加工和控制等广泛主题来培养学生。将通过每周一次的当地小学课后工程设计项目指导活动，扩大代表性不足群体在STEM领域的参与。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The goal of the proposed project is to develop computational models of ensembles of differently shaped colloidal particles as a means to control their assembly into ordered microstructures with few defects. The proposed research may enable metamaterial applications involving micro-structured colloidal-based materials for manipulation of electromagnetic radiation. Example materials include novel reflectors, gratings, polarizers, waveguides, etc. as part of sensors, solar cells, antennas, optical computers, and cloaking devices, which all require periodic structures of different shaped particles with low defect densities. The focus of the research project will be on modeling and control of ellipsoidal and super-ellipsoidal particles to enable a rich set of microstructures. Novel methods for controlling interactions using directional and time varying inputs will be developed to enable precise control of colloidal particle assembly processes.Understanding the thermodynamics and kinetics in colloidal systems is challenging and applying feedback control adds an additional layer to engineering complex responses in such systems. The goal of the proposed research is to develop minimal physically-meaningful models of stochastic dynamics to design model-based feedback control policies for the assembly of ellipsoidal and super-ellipsoidal particles. The objective is to significantly adapt and extend prior approaches to systematically define coarse grained system coordinates that capture structural features while eliminating system symmetries. The feedback control policies will be tested experimentally with tunable kT-scale interactions to design dynamic reversible assembly of different shaped particles into ordered metamaterials. The fundamental understanding of design rules and control parameters for colloidal assembly will provide new general insights beyond what is known from trial-and-error discovery. The project will train students by integrating broad topics in colloid science, fluid dynamics, materials chemistry, advanced metrology/microfabrication, and control. Broadening participation of underrepresented groups in STEM fields will be pursued through weekly mentoring activities at a local elementary after-school program focused on engineering design.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.