CAREER: Microscale contactless reconfigurable swarms with active random mutations (MICROSWARMS)

职业：具有主动随机突变的微型非接触式可重构群（MICROSWARMS）

• 批准号: 1847670
• 负责人: John Gibbs
• 金额: $ 50.3万
• 依托单位: Northern Arizona University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1847670&HistoricalAwards=false
• 关键词: CAREER; Microscale; contactless; reconfigurable; swarms

The natural world is full of examples of cooperative interactions between active components, which come together to form entities greater than the sum of their parts. For example, trillions of cells interact both physically and chemically to form highly complex biological organisms. These organisms are then capable of behaviors infinitely more diverse than those of the individual cells. When many simple parts give rise to complex behaviors, the term often used is "emergent." Self-propelled particles (SPP's) are entities capable of moving without the influence of external factors. The behavior of a collection of these SPP's can lead to emergent phenomena similar to the complex formations observed in herds of migrating animals. In general, it is difficult to predict what properties will emerge when the only information available is how the SPP's move and interact with each other. Thus, being able to perform controlled experiments on interacting SPP's is expected to help bridge this gap, but very few systems of this type are currently available. This project is dedicated to developing a system of small-scale SPP's that show emergent phenomena that are dependent upon the details of how fast the particles move, and more importantly, how they interact; both parameters can be tuned, even in real time. Another key feature of this novel system is the particles do not come into direct contact with others, mimicking behaviors such as swarming and flocking as seen in nature. These contactless particle swarms allow the study of new phenomena and make possible novel nano- and microscale material fabrication. This project will have far reaching impact on undergraduate research opportunities at Northern Arizona University (NAU). It will also impact the graduate program in Applied Physics at NAU, with a new class being developed aimed at introducing the students to the everyday activities of a professional scientist. Impact upon the local community will include the researchers working closely with a middle school on a project related to active matter as well as outreach to Native American students at the Hopi High School.Active matter consists of driven mobile entities that move and interact to form dynamic structures and patterns with properties not seen at the level of the individual self-propelled particles (SPP's). Several recent studies have been concerned with the collective and emergent phenomena observed in active colloidal matter, but the proposed research herein is unique in that the particles form clusters that do not come into direct contact, overcoming numerous current experimental limitations in this field and allowing for testing current theoretical predictions. The system, in particular, combines controllable activity using an external light source and tunable "contactless" long-range interactions arising from magnetic dipole-dipole interactions between the particles. Depending upon the geometry, these interactions can take on different forms that can be attractive, repulsive, or a combination of these. Interactions between large numbers of contactless SPP's results in collective motion that has not been demonstrated in the past and changes with particle type. Moreover, the system is ideal for the exploration of new phenomena such as shape-dependent collective behavior of complex 3D colloids when steric interactions are absent. This unique system not only allows for engineering new forms of controlled particle-particle interactions and multiple-particle collective phenomena, but these behaviors can be harnessed to fabricate new materials by active self-assembly. As many of the experimental techniques and methods in this project are excellent for introducing students to research for the first time, not only will undergraduates be an integral part of this work, but the researchers involved in this project will also work closely with STEM City to make bi-yearly visits to a middle school in Flagstaff, where the students will have the opportunity to take part in a research project on active matter. Additional efforts to disseminate this research beyond the University include outreach to K-12 students, and the larger public, in the local Flagstaff, AZ community via the Flagstaff Festival of Science and beyond by making yearly visits to the Hopi Native American Reservation for hands-on demonstrations with high school students.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.

自然界充满了活性成分之间的合作互动的例子，这些活性成分聚集在一起形成的实体大于它们各部分的总和。例如，数万亿个细胞在物理和化学上相互作用，形成高度复杂的生物有机体。然后，这些有机体的行为就比单个细胞的行为多样化得多。当许多简单的部分产生复杂的行为时，通常使用的术语是“紧急”。自推进粒子(SPP)是能够在不受外部因素影响的情况下运动的实体。这些SPP的集合的行为可以导致类似于在迁徙的动物群体中观察到的复杂队形的紧急现象。一般来说，当唯一可用的信息是SPP如何移动和相互作用时，很难预测会出现什么属性。因此，能够对相互作用的SPP进行受控实验有望帮助弥合这一差距，但目前可用的这种类型的系统很少。这个项目致力于开发一个小型SPP系统，显示紧急现象，这些现象取决于粒子运动速度的细节，更重要的是，它们如何相互作用；这两个参数都可以调整，甚至是实时的。这个新系统的另一个关键特征是粒子不与其他粒子直接接触，模仿自然界中看到的蜂拥而至和蜂拥而至的行为。这些非接触式粒子群使研究新的现象成为可能，并使新型纳米和微米材料的制造成为可能。该项目将对北亚利桑那大学(NAU)的本科生研究机会产生深远影响。这也将影响北卡罗来纳大学应用物理学的研究生课程，正在开发一个新的课程，旨在向学生介绍专业科学家的日常活动。对当地社区的影响将包括与一所中学密切合作的研究人员在一个与活性物质相关的项目上的工作，以及与霍皮高中的美国原住民学生的接触。活性物质由受驱动的移动实体组成，这些实体移动并相互作用，形成动态结构和图案，其性质在单个自推进粒子(SPP)的水平上是看不到的。最近的几项研究涉及到在活性胶体物质中观察到的集体和紧急现象，但这里提出的研究是独特的，因为粒子形成的团簇不直接接触，克服了该领域目前的许多实验限制，并允许检验当前的理论预测。具体地说，该系统结合了使用外部光源的可控活动和由粒子之间的磁偶极-偶极相互作用产生的可调“非接触式”远程相互作用。根据几何形状的不同，这些相互作用可以采取不同的形式，可以是吸引的、排斥的，也可以是这些形式的组合。大量非接触式SPP之间的相互作用导致了过去没有被证明的集体运动，并随着粒子类型的变化而变化。此外，该系统对于探索新的现象是理想的，例如当空间相互作用不存在时，复杂的3D胶体的形状依赖的集体行为。这一独特的系统不仅允许设计新形式的受控粒子-粒子相互作用和多粒子集体现象，而且可以利用这些行为通过主动自组装来制造新材料。由于这个项目中的许多实验技术和方法都很好地为学生介绍了第一次进行研究的机会，不仅本科生将成为这项工作的组成部分，而且参与这个项目的研究人员还将与STEM City密切合作，每两年访问一次弗拉格斯塔夫的一所中学，在那里学生将有机会参加一个关于活性物质的研究项目。在大学之外传播这项研究的其他努力包括通过弗拉格斯塔夫科学节和其他活动，在当地的弗拉格斯塔夫和亚利桑那州社区向K-12学生和更广泛的公众宣传，每年访问霍皮美洲原住民保护区，与高中生进行亲身实践演示。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Gravitropically Stabilized Self‐Assembly of Active Microcrystallites and Spinning Free Janus Particles

活性微晶和自由旋转 Janus 粒子的重力稳定自组装

• DOI: 10.1002/ppsc.202100232
• 发表时间: 2021
• 期刊: Particle & Particle Systems Characterization
• 影响因子: 2.7
• 作者: Nabavizadeh, Seyed Amin;Castañeda, John;Gibbs, John G.;Nourhani, Amir
• 通讯作者: Nourhani, Amir

Emergence of Ring‐Shaped Microstructures in Restricted Geometries Containing Self‐Propelled, Catalytic Janus Spheres

包含自驱动催化 Janus 球的受限几何形状中环形微结构的出现

• DOI: 10.1002/cnma.202100122
• 发表时间: 2021
• 期刊: ChemNanoMat
• 影响因子: 3.8
• 作者: Pariente, Jose Ángel;Blanco, Álvaro;López, Cefe;Gibbs, John G.
• 通讯作者: Gibbs, John G.