Collaborative Research: Active Colloids under AC Electric Fields: From Single Particle Motion to Collective Dynamics

合作研究：交流电场下的活性胶体：从单粒子运动到集体动力学

• 批准号: 1805073
• 负责人: Ning Wu
• 金额: $ 22.94万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-15 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1805073&HistoricalAwards=false
• 关键词: Collaborative; Research; Active; Colloids; under

The active transport of microscopic objects is essential for maintaining the bioactivities of living species. Although nature has evolved to possess complex biochemical motors, the development of synthetic motors lags far behind. Recently, a new type of synthetic motor driven by an alternating current electric field was developed, which hold promise for on-demand control of intelligent micro-machines. However, current electrokinetic theory cannot consistently explain their propulsion behavior under different field conditions. A complementary experimental and computational study will be performed to model the hydrodynamic flow surrounding the motors and thus reveal the underlying physical mechanisms that govern the motion of both individual and a large ensemble of motors. This research will provide the fundamental knowledge necessary for the development of technologies to manipulate micro- and nano-scale objects with both spatial and temporal regulations. Education and outreach activities, such as the development of learning modules for K-12 public schools and research summer experience programs for undergraduates, will also be developed with the goal to encourage the participation of underrepresented groups toward university science and engineering programs. The goal of this project is to understand how the electrohydrodynamics of asymmetric particles influence their active behavior ranging from single particle motion to small cluster formation to emergent collective dynamics. Three specific research tasks will be performed: (1) Elucidate the electrohydrodynamic propulsion mechanisms of dielectric particles at both low and high frequencies; (2) Reveal the intricate interplay between hydrodynamic interaction, steric effects, Brownian motion, and electrostatic interaction in the assembly of small clusters; and (3) Investigate the collective behavior of thousands of linear motors and rotating spinners. The experimental framework, by creating asymmetric properties in particles and tuning different field conditions, will allow systematic studies of the propulsion of asymmetric particles and reveal potentially different propulsion mechanisms at low and high frequencies, thus significantly advancing the field of electrokinetics. The computational methods with tunable resolution will also be able to achieve a balance between accuracy and cost, as required for studying the length and time scale of interest. A detailed comparison between experiments and numerical modeling will provide crucial insights and help reveal the underlying physics of electrohydrodynamic motors.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.

微观物体的主动运输对于维持生物物种的生物活性至关重要。尽管大自然已经进化到拥有复杂的生化马达，但合成马达的发展却远远落后。最近，开发了一种由交流电场驱动的新型合成电机，有望实现智能微机械的按需控制。然而，当前的动电理论无法一致地解释它们在不同现场条件下的推进行为。将进行补充实验和计算研究，以模拟电机周围的流体动力流动，从而揭示控制单个电机和大型电机组运动的潜在物理机制。这项研究将为开发通过空间和时间调节来操纵微米和纳米尺度物体的技术提供必要的基础知识。还将开展教育和外展活动，例如为 K-12 公立学校开发学习模块和为本科生研究暑期体验项目，以鼓励代表性不足的群体参与大学科学和工程项目。该项目的目标是了解不对称粒子的电流体动力学如何影响其活跃行为，从单粒子运动到小团簇形成再到集体动力学。将执行三项具体研究任务：（1）阐明介电粒子在低频和高频下的电流体动力推进机制； （2）揭示小团簇组装过程中流体动力相互作用、空间效应、布朗运动和静电相互作用之间错综复杂的相互作用； (3) 研究数千个线性电机和旋转器的集体行为。该实验框架通过在粒子中创建不对称特性并调整不同的场条件，将允许对不对称粒子的推进进行系统研究，并揭示低频和高频下潜在的不同推进机制，从而显着推进动电学领域的发展。根据研究感兴趣的长度和时间尺度的需要，具有可调分辨率的计算方法也将能够实现精度和成本之间的平衡。实验和数值模型之间的详细比较将提供重要的见解，并有助于揭示电流体动力电机的基本物理原理。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

Reconfigurable microbots folded from simple colloidal chains

由简单胶体链折叠而成的可重构微型机器人

• DOI: 10.1073/pnas.2007255117
• 发表时间: 2020-07
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Yang, Tao;Sprinkle, Brennan;Guo, Yang;Qian, Jun;Hua, Daoben;Donev, Aleksandar;Marr, David W. M.;Wu, Ning
• 通讯作者: Wu, Ning