Understanding and engineering geometrically frustrated self-assembly

理解和设计几何受阻的自组装

• 批准号: 2349818
• 负责人: Gregory Grason
• 金额: $ 49.66万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-06-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2349818&HistoricalAwards=false
• 关键词: Understanding; engineering; geometrically; frustrated; self

NONTECHNICAL SUMMARYThis award supports theoretical research, computation, and associated education to investigate self-assembly. Self-assembly is a process by which nanometer-scale “building blocks” spontaneously associate into multi-unit structures, which underlies structure formation of a vast range of useful materials structures in the biological and synthetic world. This project aims to advance our basic understanding of an emerging “class” of such systems, known as geometrically-frustrated assemblies (GFAs). Geometric-frustration occurs when the shape and interaction between building-blocks lead to “misfitting” arrangements when they aggregate. Such frustrated building blocks are not unlike warped puzzle pieces that fit neatly together edge to edge, but whose shape misfit requires more and more straining to piece together larger and larger patches of the puzzle. In the assemblies of these nanoscale “misfits” – composed of polymers, proteins, or colloidal particles – frustration can give rise to new mechanisms for the assembly process to “sense its size”, which are not possible in assemblies without shape misfit. The buildup of shape misfit in GFAs is related to a unique behavior known as self-limiting assembly, in which the self-assembly process can autonomously and robustly terminate at a finite number of building blocks, which itself may be predetermined based on properties of the sub-unit shape, interactions and flexibility. As such, GFAs pose a potential pathway to engineer new types of self-assembling systems, whose finite sizes can be “programmed” from the design and synthesis of building block properties. Realizing the ability to engineer the self-limiting size of material assemblies through programmed frustration may reveal potentially transformative, bottom-up pathways to fabricate functional nanostructured material architectures, such as injectable biomedical scaffolds or paintable photonic coatings, with the complexity and size control that is currently only accessible via top-down techniques like 3D printing or lithography.Capitalizing on this potential requires an understanding of the basic principles that connect the properties of nanoscale, frustrated building blocks (e.g. their shape misfit, interactions, flexibility) as well as the impacts of various types of disorder on the emergent structures they form on size scales much bigger than those subunits. This project will develop theoretical frameworks that address this core objective and facilitate the translations of theoretical principles to experimental study of synthetic and biological systems.Beyond potential impacts on materials science deriving from advancing the principles of GFA, the project will achieve several additional broader impacts. These include the training and mentorship of students (undergraduate and graduate) and a postdoctoral researcher in statistical and computational approaches to materials physics, as well as efforts of the PI to advance participation of K12 student populations from under-resourced communities in graduate student-led STEM outreach and education.TECHNICAL SUMMARYThis award supports theoretical research, computation, and associated education to investigate Geometrically-frustrated assembly (GFA). GFA is an emerging paradigm in which the local misfits between soft matter “building blocks” give rise to intra-domain stress gradients on size scales that far exceed the block dimensions. The accumulation of long-range stresses in GFA underlies a range of scale-dependent behaviors without counterpart in canonical assemblies without frustration, including the existence of a self-limiting state where the equilibrium assembly dimensions are finite, yet much larger than subunits themselves. Recent efforts aim to capitalize on this phenomenon as a means to program the mesoscopic size and morphology of self-assembled structures through the engineered misfit of synthetic building blocks, fabricated for example through state-of-the-art colloidal synthesis or DNA nanotechnology approaches. Meeting this challenge requires predictive understanding that traces microscopic features of GFA – misfit shape, interactions, and deformability – onto the finite-temperature assembly behavior that emerges at the mesoscale. Research in this project will address three critical gaps in the theoretical understanding of and engineering principles for GFA: I) the statistical physics of frustration escape to bulk assembly via both elastic (shape-flattening) and inelastic (defect-mediated) modes; II) the ability to extend the propagation of self-limiting stress by engineering floppy modes in frustrated assembly; and III) the behaviors of mixed and polydisperse frustration assemblies. The proposed aims to advance a range of modeling approaches to capture the intrinsically multiscale nature of GFA behavior. Scientific impacts of this research are further advanced through collaborations with experimentalists studying both existing GFA systems as well as those targeting “GFA by 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.

该奖项支持理论研究，计算和相关教育，以调查自组装。自组装是纳米尺度的“构建块”自发地结合成多单元结构的过程，其是生物和合成世界中大量有用材料结构的结构形成的基础。 这个项目的目的是推进我们的一个新兴的“类”这样的系统，被称为几何挫折组件（GFA）的基本理解。 几何挫折发生时，形状和积木之间的相互作用导致“不合适”的安排时，他们聚集。 这种受挫的积木就像是扭曲的拼图块，它们可以整齐地边缘到边缘地组合在一起，但其形状不匹配需要越来越多的努力来拼凑越来越大的拼图块。 在这些纳米级“失配”的组件中-由聚合物，蛋白质或胶体颗粒组成-挫折可以引起组装过程的新机制来“感知其大小”，这在没有形状失配的组件中是不可能的。 GFA中形状失配的累积与称为自限制组装的独特行为有关，其中自组装过程可以自主地且稳健地终止于有限数量的构建块，其本身可以基于子单元形状、相互作用和柔性的性质来预定。 因此，GFAs为设计新型自组装系统提供了一条潜在的途径，其有限的尺寸可以通过设计和合成构建块属性来“编程”。 实现通过编程挫折来设计材料组件的自限尺寸的能力可能会揭示制造功能性纳米结构材料架构的潜在变革性，自下而上的途径，例如可注射生物医学支架或可喷涂光子涂层，与复杂性和大小控制，目前只能通过顶部访问，利用这种潜力需要了解连接纳米级，受挫的构建块属性的基本原理。（例如，它们的形状失配，相互作用，灵活性）以及各种类型的无序对它们在比这些亚基大得多的尺寸尺度上形成的涌现结构的影响。 该项目将开发理论框架，以解决这一核心目标，并促进理论原则的合成和生物系统的实验研究的翻译。除了通过推进GFA原则对材料科学产生的潜在影响外，该项目还将实现其他几个更广泛的影响。 其中包括对学生的培训和指导（本科生和研究生）和博士后研究员在统计和计算方法，以材料物理，以及PI的努力，以促进K12学生人口的参与，从资源不足的社区在研究生主导的干外展和教育。技术总结这个奖项支持理论研究，计算，和相关的教育，以调查几何挫折组装（GFA）。GFA是一种新兴的范例，其中软物质“积木”之间的局部失配引起远远超过块尺寸的尺寸尺度上的域内应力梯度。 长程应力在GFA中的积累是一系列尺度依赖行为的基础，而在没有挫折的规范组装中没有对应物，包括存在自限状态，其中平衡组装尺寸是有限的，但比亚基本身大得多。 最近的努力旨在利用这一现象作为一种手段，以编程介观尺寸和形态的自组装结构，通过工程错配的合成积木，制造，例如通过国家的最先进的胶体合成或DNA纳米技术方法。 迎接这一挑战需要预测性的理解，跟踪GFA的微观特征-错配形状，相互作用和变形性-到有限温度组装行为，出现在中尺度。 在这个项目中的研究将解决三个关键差距的理论理解和工程原则的GFA：一）统计物理的挫折逃逸散装组装通过弹性（形状扁平化）和无弹性（缺陷介导的）模式; II）通过在受抑组件中设计松弛模式来扩展自限应力的传播的能力;混合多分散阻挫集合体的行为。 建议的目的是推进一系列的建模方法，以捕捉GFA行为的内在多尺度性质。 通过与研究现有总建筑面积系统以及针对“设计总建筑面积”的实验人员合作，进一步推进了这项研究的科学影响。该奖项反映了NSF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。