Photocatalytic Active Matter

光催化活性物质

• 批准号: 1703322
• 负责人: John Gibbs
• 金额: $ 13.29万
• 依托单位: Northern Arizona University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1703322&HistoricalAwards=false
• 关键词: Photocatalytic; Active; Matter

Active matter is matter composed of particles that can convert energy into motion. Examples of active matter are schools of fish, flocks of birds, and bacteria. Most examples of active matter are biological in origin, but presently there is a significant amount of research into synthetic systems. This concept is of interest because of the potential for controllable and reversible assembly of larger structures, for the triggered capture, delivery, and release of cargo such as drugs, and for using it as a tool for understanding biological processes that are out of equilibrium. This proposal aims to identify and develop methods for moving and manipulating nanometer-to-micron sized active particles in fluids. For example, active spherical particles can be produced by coating one hemisphere with a chemical that can react with another compound dissolved in the fluid. Since the uncoated hemisphere is inert, the particle has a preferred direction of motion related to the varying concentration of the dissolved chemical. However, systems such as this cannot easily be switched on and off; if the fuel is present, the particles remain active and moving. This research project is exploring a novel system that can be switched on and off through illumination by light. Special fabrication methods are being used to produce light-activated particles with complex shapes in order to identify the role shape has in how active particles move and assemble into larger structures. Significant features of this research project are that both graduate and undergraduate students are deeply involved in the research and that aspects of the research are being incorporated into an undergraduate laboratory class. The researchers involved in this project are bringing project-related demonstrations to Hopi High School on the Hopi Reservation in Northern Arizona in an effort to engage students in science who are underrepresented in STEM fields. Active colloids have received considerable attention recently, but a number of questions remain unanswered regarding the mechanisms of motion and particle self-assembly. In addition, the realization of functional nanomachines, for example for cargo delivery, is still in its infancy. This research project aims to study a photocatalytically active system, in which the activity may be easily switched on and off. Specialized fabrication techniques, based on glancing angle deposition (GLAD), are being used to produce active colloidal particles with complex shapes and material compositions. These anisotropic particles are being used to gain insight into how to control particle motion and to investigate the role of shape in self-assembly of the particles. This system of photocatalytic active particles of various shapes may make possible new applications and a deeper understanding of propulsion at the nanoscale. Ultimately, the researchers intend to control the pick-up and release of cargo at the mesoscale using the self-assembly of these active particles. The research project also includes a significant educational and outreach component, including the development of a nanoscience based course, a new experimental module for an undergraduate lab course, and the involvement of Native American students from Northern Arizona.

活性物质是由能将能量转化为运动的粒子组成的物质。活跃物质的例子有鱼群、鸟群和细菌。大多数活性物质的例子是生物起源，但目前有大量的研究合成系统。这一概念之所以引起人们的兴趣，是因为它有可能控制和可逆地组装更大的结构，用于触发药物等货物的捕获、输送和释放，并将其用作理解失去平衡的生物过程的工具。该提案旨在确定和开发移动和操纵流体中纳米到微米大小的活性颗粒的方法。例如，可以通过在一个半球涂上一种化学物质来生产活性球形颗粒，这种化学物质可以与溶解在液体中的另一种化合物发生反应。由于未涂覆的半球是惰性的，粒子有一个与溶解的化学物质浓度变化有关的优选运动方向。然而，像这样的系统不容易打开和关闭；如果有燃料存在，粒子就会保持活跃和移动。这个研究项目正在探索一种可以通过光照来开关的新系统。特殊的制造方法被用于生产具有复杂形状的光活化粒子，以确定形状在活性粒子如何移动和组装成更大的结构中的作用。本研究项目的显著特点是研究生和本科生都深入参与研究，并且研究的各个方面都被纳入本科生实验课。参与该项目的研究人员将项目相关的演示带到亚利桑那州北部霍皮保留地的霍皮高中，以吸引在STEM领域代表性不足的科学学生。活性胶体近年来受到了广泛的关注，但关于其运动机制和粒子自组装等问题仍未得到解答。此外，功能性纳米机器的实现，例如用于货物运输，仍处于起步阶段。本研究项目旨在研究一种光催化活性体系，其活性可以很容易地打开和关闭。基于掠角沉积（GLAD）的专门制造技术正被用于生产具有复杂形状和材料成分的活性胶体颗粒。这些各向异性粒子被用来深入了解如何控制粒子运动，并研究形状在粒子自组装中的作用。这种由各种形状的光催化活性粒子组成的系统可能会有新的应用，并对纳米尺度上的推进有更深入的了解。最终，研究人员打算利用这些活性粒子的自组装，在中尺度上控制货物的吸收和释放。该研究项目还包括一个重要的教育和推广组成部分，包括纳米科学基础课程的开发，本科实验课程的新实验模块，以及来自北亚利桑那州的美国原住民学生的参与。

项目成果

Light-Activated, Multi-Semiconductor Hybrid Microswimmers

• DOI: 10.1002/smll.201801860
• 发表时间: 2018-08-09
• 期刊: SMALL
• 影响因子: 13.3
• 作者: O'Neel-Judy, Etude;Nicholls, Dylan;Gibbs, John G.
• 通讯作者: Gibbs, John G.

Engineering the Dynamics of Active Colloids by Targeted Design of Metal–Semiconductor Heterojunctions

• DOI: 10.1002/admi.201801894
• 发表时间: 2019-02
• 期刊: Advanced Materials Interfaces
• 影响因子: 5.4
• 作者: J. Gibbs;S. Sarkar;Andrew Leeth Holterhoff;Mingyang Li;John Castañeda;Justin Toller

Shape-Dependent Motion of Structured Photoactive Microswimmers

• DOI: 10.1021/acsami.8b01940
• 发表时间: 2018-05-30
• 期刊: ACS APPLIED MATERIALS & INTERFACES
• 影响因子: 9.5
• 作者: Nicholls, Dylan;DeVerse, Andrew;Gibbs, John G.
• 通讯作者: Gibbs, John G.