Large Scale Synthesis of Near-Monodisperse Gold Nanorods and their Assembly into 3D Anisotropic Single Crystals

近单分散金纳米棒的大规模合成及其组装成 3D 各向异性单晶

• 批准号: 1105878
• 负责人: Anatoly Kolomeisky
• 金额: $ 37.8万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-15 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1105878&HistoricalAwards=false
• 关键词: Large; Scale; Synthesis; Near; Monodisperse

TECHNICAL SUMMARY This research project, supported by the Solid State and Materials Chemistry (SSMC) Program in the Division of Materials Research, National Science Foundation aims to study kinetically-controlled syntheses of anisotropic gold nanostructures and their colloidal crystallization in aqueous media. While numerous 3D crystals of spherical particles are known, there are no analogous systems composed of rod-like building blocks. This is because nearly all existing syntheses of nanorods cannot control their length, which often makes them unsuitable for long range 3D crystallization. Seed-mediated synthesis of gold nanorods is a rare example of the reaction producing rods that are fairly well-defined in terms of their length. However, this method is currently non-scalable and cannot offer a sufficient quantity of nanorods to conduct a comprehensive study of their crystallization. This project will develop a route that can scale the synthesis up to four orders of magnitude. The key of the proposed approach is based on uniform amplification of preformed nanorods by reducing residual gold ions on their surface. Preliminary findings show that this goal can be achieved if the rate of reduction is very low, which allows for complete suppression of random nucleation events. Once the large quantities of near-monodisperse nanorods are produced, their crystallization into 3D single crystals will be systematically studied. The project will determine the role of various parameters such as size distribution and purity of rods, their interaction with the underlying substrates, and the rate of solvent evaporation. Of particular importance will be the role of CTAB surfactant that must be present in solution during crystallization. When the best combination of structural and physical variables is identified, periodic arrays of colloidal single crystals will be assembled on lithographically patterned substrates. Measurements of optical, electrical, and mechanical properties of crystals along and perpendicular to the axes of nanorods will be performed in order to assess their direction-dependent vectorial nature.NON-TECHNICAL SUMMARY Significant interest in gold nanoparticles with controlled shapes has grown dramatically in the past decade. However, they are often too difficult to make and/or purify. The current commercial price of gold nanorods is more than 7,000 times the price of bulk gold. Therefore, a development of more efficient large-scale synthesis will resolve the issue of their accessibility, which is the main bottleneck of their real-life applications in anticancer therapy, military devices, and invisible cloak technology. Better understanding of mechanisms that govern the assembly of non-spherical particles into large crystals will offer novel types of nanomaterials with direction-dependent properties. The new scientific knowledge generated in the course of this project will be widely disseminated via information sharing techniques and Web2.0 communications. Video materials containing a detailed demonstration of the synthesis of gold nanorods and real-time imaging of 3D crystals by optical and electron microscopy will be posted on the YouTube and Rice University web sites. Of particular importance will be the interactions with science teachers from local middle schools that have a large population of minority students. The PI and his graduate students will use their extensive experience with molecular graphics for 3D visualization of nanostructures and colloidal assemblies in order to create a unique type of activity in Houston public schools that currently collaborate with Rice University. In addition, an exciting outreach activity is planned at the intersection of science and art, which will involve collaborative interactions with the Museum of Fine Arts, Houston.

技术摘要该研究项目在材料研究部的固态和材料化学（SSMC）计划的支持下，国家科学基金会旨在研究各向异性金纳米结构的动力控制的合成及其在水中培养基中的胶体结晶。尽管已知许多球形颗粒的3D晶体，但没有类似杆状构件组成的类似系统。这是因为几乎所有现有的纳米棒合成都无法控制其长度，这通常使它们不适合远程3D结晶。种子介导的金纳米棒的合成是产生反应棒的罕见例子，这些棒在其长度方面定义得很好。但是，该方法目前是不可算的，无法提供足够数量的纳米棒来对其结晶进行全面研究。该项目将开发一条可以将合成扩展到四个数量级的路线。所提出的方法的关键是基于通过减少表面残留的金离子来统一扩增预制的纳米棒。初步发现表明，如果还原速率非常低，则可以实现此目标，从而可以完全抑制随机成核事件。一旦产生了大量近距离分散的纳米棒，将系统地研究它们的结晶为3D单晶。该项目将确定各种参数的作用，例如尺寸分布和杆的纯度，它们与基础底物的相互作用以及溶剂蒸发速率。特别重要的是，在结晶过程中必须存在溶液中CTAB表面活性剂的作用。当确定结构和物理变量的最佳组合时，胶体单晶的周期性阵列将组装在光刻的图案化底物上。将对沿纳米棒轴和垂直于纳米棒轴的光学，电气和机械性能进行测量，以评估其方向依赖性的矢量性质。非技术总结具有控制形状的金纳米颗粒的重要兴趣已在具有控制形状的金色中显着增长。过去十年。但是，它们通常很难制作和/或净化。当前黄金纳米棒的商业价格是批量黄金价格的7,000多倍。因此，更有效的大规模合成的发展将解决其可及性问题，这是他们在抗癌治疗，军事设备和无形的斗篷技术中现实生活中应用的主要瓶颈。更好地理解管理非球体颗粒为大晶体的机制将提供具有方向依赖性特性的新型纳米材料。该项目过程中产生的新科学知识将通过信息共享技术和Web2.0通信广泛传播。 YouTube和Rice University网站上将发布包含金纳米棒合成和3D晶体的实时成像的详细演示的视频材料。特别重要的是，将与来自当地中学的科学老师进行互动，这些教师拥有大量少数族裔学生。 PI和他的研究生将利用他们在分子图形方面的丰富经验来对纳米结构和胶体组件的3D可视化，以便在目前与莱斯大学合作的休斯顿公立学校中创建独特的活动。此外，计划在科学与艺术的交集中进行激动人心的外展活动，该活动将涉及与休斯敦美术博物馆的合作互动。