Dynamic Pathways to Crystallization of DNA-Coated Colloids

结晶——原子、分子或其他小粒子的自发排列——几个世纪以来一直吸引着人类。对结晶的研究使我们对物质的理解有了根本性的发展，例如，水是如何结冰的。结晶也是从微电子到制药业等各种重要行业的核心。然而，尽管结晶在基础科学和应用科学中无处不在，但关于结晶动力学的许多谜团仍然存在。本研究项目的科学目标是了解晶体形成的动态途径，并利用这种理解开发新的方法来制造具有奇异材料特性的宏观单晶。这项研究将揭示关于结晶物理的新基础知识，并为未来可编程纳米材料奠定基础，这可能会在光通信、光收集和其他下一代技术中找到应用。该研究项目还培养了软凝聚态物理跨学科领域的学生，并使公众参与有关科学的对话。更具体地说，研究团队正在开发以学生为主导、以学生为中心的暑期项目，旨在为本科生提供实验室实践培训，同时通过创建研究人员社区和加强团队凝聚力来促进多样性和包容性。该团队还与当地一家科学博物馆开展了推广活动，重点是提高周围社区的兴趣和科学素养。技术摘要：本研究项目的目标是了解控制动态结晶途径的基本热力学和动力学驱动力，并制定控制这些途径的实用策略，以从dna包覆胶体中创建新的光学超材料。拟议的研究是围绕两个具体的研究组织的。在第一项研究中，研究小组正在探索成核和生长的动力学是如何从成对相互作用势中产生的，以及母流体相和子晶体相的细节。研究小组使用一种实验方法，将基于液滴的微流体与光学显微镜相结合，系统地量化并行运行的数百个实验的完整动态演变。他们还开发了一套基于多价相互作用统计力学、经典成核理论和晶体生长经典理论的理论工具，以揭示结晶途径的微观信息，并创建一个数据驱动的框架来指导他们的实验设计。在第二项研究中，研究小组正在利用他们对成核和生长的基本理解来创建合理的非平衡协议，以形成具有规定结构的单晶，这可以用于未来的光子学和等离子体学应用。在这里，他们从传统的工业实践中汲取灵感，如缓慢的温度斜坡，温度循环，多步骤成核和生长协议，以及种子成核。虽然现有的研究主要集中在扩大平衡状态下形成的静态结构的多样性，但研究小组正在努力了解这些结构自组装的丰富动态途径，并开发控制这些途径的新方法，以便从胶体中组装宏观可编程材料。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。

Nontechnical AbstractCrystallization—the spontaneous ordering of atoms, molecules, or other small particles—has fascinated humankind for centuries. The study of crystallization has led to fundamental developments in our understanding of matter, for example, how water freezes to become ice. Crystallization is also central to a wide variety of important industries, ranging from microelectronics to pharmaceuticals. Yet, despite the ubiquity of crystallization in both fundamental and applied science, many mysteries regarding the dynamics of crystallization remain. The scientific objective of this research project is to understand the dynamic pathways by which crystals form and to use that understanding to develop new methods for making macroscopic single crystals with exotic materials properties. The research will reveal new fundamental knowledge about the physics of crystallization and lay the foundation for programmable nanomaterials of the future, which could find applications in optical communications, light-harvesting, and other next-generation technologies. The research project also trains students in the interdisciplinary field of soft condensed matter physics and engages the public in conversations about science. More specifically, the research team is developing student-led, student-focused summer programs designed to provide undergraduate students with practical hands-on training in the laboratory, while also promoting diversity and inclusion by creating a community of researchers and reinforcing group cohesion. The team is also creating outreach activities with a local science museum focused on enhancing interest and scientific literacy in the surrounding community.Technical AbstractThe goal of this research project is to understand the fundamental thermodynamic and kinetic driving forces that govern the dynamic pathways to crystallization, and to develop practical strategies for controlling those pathways to create new optical metamaterials from DNA-coated colloids. The proposed research is organized around two specific studies. In the first study, the research team is exploring how the kinetics of nucleation and growth emerge from the pair-interaction potential, as well as the details of the parent fluid phase and the child crystal phase. The research team uses an experimental approach combining droplet-based microfluidics with optical microscopy to systematically quantify the full dynamic evolution of hundreds of experiments running in parallel. They are also developing a suite of theoretical tools based on the statistical mechanics of multivalent interactions, classical nucleation theory, and classical theories of crystal growth to uncover microscopic information about the crystallization pathways and to create a data-driven framework to guide the design of their experiments. In the second study, the research team is utilizing their fundamental understanding of nucleation and growth to create rational nonequilibrium protocols for forming single crystals with prescribed structures, which could be used in future applications in photonics and plasmonics. Here they draw inspiration from traditional industrial practices, such as slow temperature ramps, temperature cycling, multistep nucleation and growth protocols, and seeded nucleation. While existing studies have focused primarily on expanding the diversity of static structures that form in equilibrium, the research team is working to understand the rich dynamical pathways by which those structures self-assemble and to develop new approaches to control those pathways in order to assemble macroscopic programmable materials from colloids.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.