Collaborative Research: Individual and Collective Dynamics of Marangoni Surface Tension Effects between Particles

本研究的主要目的是研究由于表面活性剂的释放、表面反应或颗粒释放热量而引起的表面张力梯度而导致的活性颗粒在流体界面上的运动。通过将化学能转化为机械能，这些自我推进的马兰戈尼粒子，无论是在个体层面还是作为一个整体，都可以承担类似生物有机体的功能。这项研究的发现将确定设计微型自推进粒子的指导原则，这可能导致机器人，微流体和生物医学工程的革命性创新。这些微型冲浪机器人可以执行目前非常困难甚至不可能完成的任务。该项目的成果也将促进主动自组装技术的发展，该技术可用于快速制造小型结构材料。此外，本研究的结果将揭示自产生的马兰戈尼应激在生活在流体界面的耐抗生素感染细菌的定植和生存中的作用。因此，这些研究提供的新见解可以促进设计更有效的抗生素。该项目支持的研究生将获得流体动力学、输运和界面现象以及高性能模拟方面的高级培训。除了整合到现有的工程课程中，还将创建Marangoni推进和流驱动自组装界面的教育模块，并在推广活动中展示。将通过教育和外联活动促使代表性不足的少数民族和女学生积极参与。这项研究将建立对马兰戈尼驱动的活性粒子单独和群体运动的基本理解，这些运动出现在从机器人和制造业到生物学和医学的各种环境中。通过引入综合的数值-理论-实验框架来研究自推进界面结合活性粒子的流体动力学，将创造新的知识。该项目的成功完成将为Marangoni冲浪者开发基于物理的速度和稳定性图表，作为定制系统参数的工程指南，以在各种应用中获得所需的性能特征。此外，本研究的结果将通过开发一种高性能的模拟技术来推进最先进的粒子负载界面流动的多物理场计算分析，该技术能够捕捉活性粒子的运动、释放物质或热量的传输以及界面变形和动力学之间复杂的相互作用。该项目的具体目标是：(i)表征无界域中单个粒子的马兰戈尼推进；（ii）研究约束对粒子推进动力学的影响；(3)分析自行冲浪者的平移和转动稳定性；（四）探索活性粒子的自组装和集体冲浪。

The principal goal of this research is to investigate the motion of active particles at fluidic interfaces due to a gradient of surface tension stemming from the discharge of a surface-active agent, a surface reaction, or from the release of heat by the particle. Powered by converting chemical energy into mechanical work, these self-propelled Marangoni particles, both at the individual level and as a collection, can bring to bear functionalities that resemble those of biological organisms. The findings of this study will determine the guiding principles for designing miniature self-propelled particles, which can lead to transformative innovations in robotics, microfluidics, and biomedical engineering. These tiny surfing robots can potentially execute missions that are currently very difficult or even impossible to accomplish. The results of this project will also give rise to the development of active self-assembly techniques, which can be used for rapid fabrication of small-scale structured materials. Further, the outcome of this research will shed light on the role of self-generated Marangoni stresses in the colonization and survival of antibiotic-resistant infectious bacteria living at fluidic interfaces. The new insight provided by these studies can thus facilitate the design of more effective antibiotics. Graduate students supported by the project will gain advanced training in fluid dynamics, transport and interfacial phenomena, and high-performance simulations. Educational modules on Marangoni propulsion and flow-driven self-assembly at interfaces will be created and showcased during outreach activities, in addition to being integrated into the existing engineering courses. Active involvement of underrepresented minority and female students will be pursued via educational and outreach activities.This research will establish a fundamental understanding of the Marangoni-driven motion of active particles alone and in groups, which appear in various contexts ranging from robotics and manufacturing to biology and medicine. New knowledge will be created by introducing a comprehensive numerical-theoretical-experimental framework to examine the hydrodynamics of self-propelled interface-bound active particles. The successful completion of this project will lead to the development of a physics-based speed and stability charts for Marangoni surfers that serves as engineering guidelines for tailoring the system parameters to elicit the desired performance characteristics in a variety of applications. Additionally, the outcome of this study will advance the state-of-the-art in multi-physics computational analysis of particle-laden interfacial flows by developing a high-performance simulation technique capable of capturing the intricate interplay between the motion of the active particles, transport of released species or heat, and interface deformation and dynamics. The specific objectives of this project are: (i) characterizing the Marangoni propulsion of single particles in unbounded domains; (ii) investigating the influence of confinement on the propulsion dynamics of particles; (iii) analyzing the translational and rotational stability of self-propelled surfers; and (iv) exploring the self-assembly and collective surfing of active particles.