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

这项研究的主要目的是研究活性颗粒在流体界面上的运动，这是由于表面活性剂的释放、表面反应或颗粒放热引起的表面张力梯度造成的。通过将化学能转化为机械功，这些自我推进的Marangoni粒子，无论是在个人层面还是作为集合，都可以带来类似于生物有机体的功能。这项研究的结果将确定设计微型自行式颗粒的指导原则，这可能导致机器人、微流体和生物医学工程方面的变革性创新。这些微小的冲浪机器人可能会执行目前非常困难甚至不可能完成的任务。该项目的成果还将促进主动自组装技术的发展，这种技术可以用于快速制造小规模结构材料。此外，这项研究的结果将揭示自我产生的Marangoni压力在生活在流体界面的耐药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、传输和界面现象以及高性能模拟方面的高级培训。除了融入现有的工程课程外，还将在外联活动期间创建和展示关于Marangoni推进和界面流动驱动自组装的教学模块。这项研究将建立对Marangoni驱动的活动粒子单独和成组运动的基本理解，这些运动出现在从机器人和制造到生物和医学的各种背景中。通过引入一个全面的数值-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导致为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，这项研究的结果将通过开发一种能够捕捉活性粒子运动、释放的物质或热的传输以及界面变形和动力学之间的复杂相互作用的高性能模拟技术，来推进含颗粒界面流动的多物理计算分析的发展。该项目的具体目标是：(1)表征无界区域中单个粒子的Marangoni推进；(2)调查限制对粒子推进动力学的影响；(3)分析自行冲浪者的平移和旋转稳定性；以及(4)探索活跃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.