Active colloids with tunable interactions in liquid crystals

液晶中具有可调节相互作用的活性胶体

基本信息

批准号：
1905053
负责人：
Oleg Lavrentovich
金额：
$ 54万
依托单位：
Kent State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-07-01 至 2023-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1905053&HistoricalAwards=false
关键词：
Active colloids tunable interactions liquid

项目摘要

Nontechnical abstract:Mankind is increasingly dependent on technologies of transportation. Over centuries, the thrust has been on development of macroscopic devices such as cars, planes, ships that are larger than the human beings. The new challenge is to develop miniature systems that could rectify the energy of environment into directed motion at the scale of micrometers. In the future, these micromachines are expected to interact with biological tissues and individual cells, serve as elementary units of soft microrobots, deliver microscopic quantities of drugs or other useful chemicals, work as energy harvesters, responsive actuators, microscale mixers and separators. Electric field is considered as one of the most effective means in powering the transport of matter at microscale. Most of the studies of microdynamics are performed for an isotropic environment, such as water, which does not provide a clear sense of direction for electrically powered microsystems. The goal of the project is to learn how one can control dynamics of microparticles by anisotropic fluids, with properties that depend on the direction in space. These fluids are known as liquid crystals. Anisotropy of liquid crystals under the action of the electric field is already used in informational displays of modern computers, smartphones and TV sets. The project will explore how to use liquid crystals as a medium that enables and commands dynamics and interactions of microparticles. The project will advance the knowledge of mechanisms defining dynamics of soft matter at microscopic scales and potentially contribute to the technologies of future micromachines. Technical abstract:Collective out-of-equilibrium spatiotemporal dynamics of microscopic particles in the so-called active matter is a fascinating area of intense studies. Depending on the type of interactions, active matter develops various scenarios of behavior, from coordinated collective unidirectional motion to turbulent-like flows. The project will explore how the electric field controls dynamics of colloidal particles and their interactions at microscale, using methods such as optical microscopy, confocal microscopy and particle velocimetry. The project will answer a question whether and how the seemingly chaotic dynamics of active matter can be controlled by an ordered environment of a liquid crystal. The potential transformative value is in understanding the mechanisms by which the orientational order can command interactions and collective motion in ensembles of electrically powered active particles. The orientational order of the proposed LC environment imposes long-range anisotropic elastic and hydrodynamic interactions and propulsion modes that are absent in isotropic fluids. The project will advance the knowledge of electro-hydrodynamics of LCs and colloids, physics of out-of-equilibrium active matter. Application of already tested methods such as three-dimensional confocal microscopy, particle imaging velocimetry, patterned photo-alignment and electro-optics will ensure that the new knowledge is based on a solid experimental background. The project will provide a new platform to design and control ensembles of active particles, which has the potential for enormous societal benefits in areas ranging from existing technologies (such as improved electrophoretic displays) to the technologies of the future, which would exploit the unique ability of active colloids to transduce energy from the environment into systematic movement, to control the flow of matter, to serve as important elements of micromachines. The project will educate a new and diverse generation of scientists with fundamental and technological expertise in soft and active matter.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.

非技术摘要：人类越来越依赖运输技术。几个世纪以来，这种推力一直在开发宏观设备，例如汽车，飞机，船只，比人类大。新的挑战是开发可以将环境能量纠正为微米的定向运动的微型系统。将来，这些微机器有望与生物组织和单个细胞相互作用，作为软微型机器人的基本单位，提供微观量的药物或其他有用的化学物质，可作为能量收割机，响应式执行器，微观搅拌器和分离器。电场被认为是在微观上为物质运输供电的最有效手段之一。大多数对微动力学的研究都是针对各向同性环境（例如水）进行的，该研究并不能为电力微型系统提供明显的方向感。该项目的目的是学习如何通过各向异性流体来控制微粒动力学，其特性取决于空间的方向。这些流体称为液晶。电场作用下液晶的各向异性已经用于现代计算机，智能手机和电视机的信息显示。该项目将探索如何使用液晶作为启用和命令微粒动力和相互作用的介质。该项目将促进在微观尺度上定义软物质动力学的机制的知识，并有可能有助于未来的微机械技术。技术摘要：所谓的活性物质中微观颗粒的集体外部时空动力学是一个令人着迷的深入研究领域。根据相互作用的类型，主动物质会发展出各种行为的情况，从协调的集体单向运动到湍流样流。该项目将使用光学显微镜，共聚焦显微镜和粒子速度计等方法探讨电场如何控制胶体颗粒及其相互作用的动力学及其相互作用。该项目将回答一个问题，是否以及如何通过液晶的有序环境控制活跃物质的看似混乱的动力学。潜在的变革价值在于理解方向秩序可以在电力活性颗粒的集合中命令相互作用和集体运动的机制。所提出的LC环境的方向顺序施加了各向同性流体中不存在的远距离各向异性弹性和流体动力相互作用和推进模式。该项目将促进LCS和胶体的电融化动力学知识，即非平衡活性物质的物理学。已经测试过的方法的应用，例如三维共聚焦显微镜，粒子成像速度计，图案化的光相位和电镜，将确保新知识基于坚实的实验背景。该项目将提供一个新的平台来设计和控制主动颗粒的团结，该平台有可能在现有技术（例如改善的电泳展示）到未来技术的领域获得巨大的社会利益，这将利用活性胶体的独特能力从环境转移到系统的运动中，以控制Materach的元素，从而将环境从环境转移到系统流动中，并能够将其转换为Internocar的流动。该项目将教育一系列新的科学家，具有软体和主动物质方面的基本和技术专业知识。该奖项反映了NSF的法定使命，并使用基金会的知识分子优点和更广泛的影响评估标准，认为值得通过评估来获得支持。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Ferroelectric nematic liquid crystal, a century in waiting

DOI：
10.1073/pnas.2008947117
发表时间：
2020-06-30
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
影响因子：
11.1
作者：
Lavrentovich, Oleg D.
通讯作者：
Lavrentovich, Oleg D.

Defects in bent-core liquid crystals

弯芯液晶的缺陷