Janus Nanoparticles by Interfacial Engineering

Janus 纳米粒子的界面工程

• 批准号: 0804049
• 负责人: Shaowei Chen
• 金额: $ 26万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0804049&HistoricalAwards=false
• 关键词: Janus; Nanoparticles; Interfacial; Engineering

This award to University of California Santa Clare by the Solid State Materials Chemistry program in the Division of Material Research is study the development of an effective protocol based on interfacial engineering for the preparation of nanometer-sized Janus particles, and examination of these functional nanomaterials as unique building blocks for the fabrication of more complicated architectures and assemblies. Specifically, hydrophobic alkanethiolate-protected gold nanoparticles will be used as the initial illustrating examples. By taking advantage of the impeded interfacial mobility of the particles at the air-water interface upon mechanical compression (the Langmuir method), the surface exchange reactions with hydrophilic thiol derivatives that are injected into the aqueous subphase will be confined to only one side of the particle surface, and hence the formation of amphiphilic nanoparticles. A wide array of analytical tools will then be employed to carefully examine the structures of the resulting particles and their organized ensembles, including contact angle measurements, scanning probe microscopy (e.g., AFM and STM), and spectroscopies (UV-visible, FTIR, NMR, dynamic light scattering, etc). Further manipulation of the Janus nanoparticles will focus on deliberate variation of the chemical structure of ligands and the metal cores. Overall, the capability of engineering the structure and properties of nanoscale building blocks for controlled assembly represents a critical first step towards device fabrication and integration. In this project, student researchers will benefit from the interdisciplinary nature of the work by learning the state of the art of nanoparticle synthesis, characterization, and assembly. Furthermore, some of the activities will also be closely integrated with several outreach programs targeting minority, women, and disadvantaged undergraduate students.In this project Prof. Shaowei Chen and his students at the University of California Santa Cruz, will develop an effective approach to the preparation of nanometer-sized particle materials that exhibit hydrophobic characters on one face and hydrophilic on the other. These particles are analogous to the dual-face Roman god, Janus, and hence Janus nanoparticles. The motivation is that by segregating the hydrophobic ligands from the hydrophilic ones on the particle surface, the particles may behave like the surfactant molecules of detergents, leading to directional assembly of the particles into organized structures. Gold nanoparticles stabilized by a monolayer of alkanethiolates will be used as the starting materials. Experimentally, a monolayer of the particles will be first formed on the water surface; and by mechanical compression (the Langmuir method) the mobility of the particles will be impeded because of intercalation of the organic protecting ligands from neighboring particles. Injection of a hydrophilic ligand into the water phase will then initiate ligand exchange reactions that are limited only to the bottom half of the particles, and hence the production of Janus nanoparticles. Further work will be extended to other nanoparticle materials. The resulting particles will then be used for controlled assembly into organized structures with unique functional characteristics. Student researchers will benefit from the interdisciplinary nature of the work by learning the state of the art of nanoparticle synthesis, characterization, and assembly. The research activities will also be integrated with various outreach programs targeting minority, women, and disadvantaged undergraduate students.

该奖项由材料研究部的固态材料化学项目授予加州大学圣克莱尔分校，该奖项旨在研究基于界面工程的有效方案的开发，以制备纳米尺寸的Janus颗粒，并研究这些功能纳米材料作为制造更复杂建筑和组件的独特构建块的能力。具体地说，疏水性硫代烷基保护的金纳米颗粒将被用作最初的例证。通过利用机械压缩时空气-水界面粒子的界面流动性受阻(朗缪尔法)，与注入水相亚相的亲水性硫醇衍生物的表面交换反应将仅限于粒子表面的一侧，从而形成两亲性纳米粒子。然后将使用一系列广泛的分析工具来仔细检查所得到的颗粒及其有序集合的结构，包括接触角测量、扫描探针显微镜(例如AFM和STM)和光谱分析(UV-可见光、FTIR、核磁共振、动态光散射等)。对Janus纳米粒子的进一步操作将集中在故意改变配体和金属核心的化学结构上。总体而言，设计用于受控组装的纳米级构建块的结构和性能的能力是迈向器件制造和集成的关键第一步。在这个项目中，学生研究人员将从这项工作的跨学科性质中受益，学习纳米颗粒合成、表征和组装的最新技术。此外，一些活动还将与针对少数族裔、女性和弱势本科生的几个外展项目紧密结合。在这个项目中，加州大学圣克鲁斯分校的陈少伟教授和他的学生将开发一种有效的方法来制备纳米颗粒材料，这种材料一方面具有疏水特性，另一方面具有亲水性。这些粒子类似于罗马双面神Janus，因此也类似于Janus纳米粒子。其动机是通过分离颗粒表面的疏水配体和亲水配体，颗粒的行为可能像洗涤剂的表面活性分子一样，导致颗粒定向组装成有组织的结构。由烷基硫代硫酸盐单层稳定的金纳米颗粒将被用作起始材料。在实验上，首先在水面上形成一层颗粒的单层，然后通过机械压缩(朗缪尔法)，由于有机保护配体插入邻近颗粒的夹层，颗粒的流动性将受到阻碍。将亲水性配体注入水相后，将启动仅限于颗粒下半部分的配体交换反应，从而产生Janus纳米颗粒。进一步的工作将扩展到其他纳米材料。然后，生成的颗粒将用于受控组装成具有独特功能特征的有组织的结构。学生研究人员将从这项工作的跨学科性质中受益，学习纳米粒子合成、表征和组装的最新技术。研究活动还将与针对少数族裔、女性和弱势本科生的各种外展计划相结合。