Self-Assembly of Plasmonic Nanoclusters Mediated by Localized Steric Repulsion

1236309PI: pozzo利用等离子体效应的新技术的实施在很大程度上取决于提高我们用纳米级金属构件可靠而经济地生产复杂结构的能力。不幸的是，大量纳米材料的组织方式是“自下而上”。可扩展的、具有成本效益的、实现精确结构控制的策略仍然有限。本项目将研究一种利用局部空间斥力和短距离引力将纳米粒子构建块组装成复杂结构的新策略。在这种新方法中，结构团簇的形成将通过使用含有末端接枝聚合物混合物的工程纳米颗粒表面来控制空间排斥和小功能分子来诱导吸引力。通过改变表面组成来控制粒子的组装和操纵多粒子结构的形态，可以精确地调节空间排斥和吸引相互作用。使用这种强大的策略，将产生具有可控光学和电子特性的各种胶体团。x射线和中子的小角度散射将用于选择性地探测纳米粒子的结构（SAXS）和聚合物的结构（SANS），以便对组装过程进行完整和自一致的描述。结构实验将通过与模拟的直接比较加以补充。该项目的主要目标是：1)通过实验确定聚合物相互作用在介导纳米颗粒自组装中的作用；2)降低自组装团簇的结构多分散性；3)用蒙特卡罗模拟预测平衡团簇结构；4)增加胶体分子的结构多样性。实现这些目标将大大有助于利用纳米颗粒团簇的等离子体应用的进步。等离子体技术利用了可见光和小金属粒子中离域电子云之间独特的相互作用。例如，等离子体效应被用于开发传感器，用于快速识别复杂样品中的痕量化学物质和环境污染物。他们还推进了侵入性更小、更有效的医疗诊断和治疗工具，如光声成像和光热癌症治疗。等离子体方法也被用于开发比现有技术更高效、更便宜的先进太阳能电池。然而，这些和其他应用的成功部署需要在具有可控光学和电子特性的纳米结构的可扩展制造方面取得重大进展。该项目将研究一种适用于制造大量等离子体纳米材料的新方法，同时保持精确的结构控制，并采用可扩展、健壮和通用的方法。

1236309PI: PozzoThe implementation of new technologies harnessing plasmonic effects depends strongly on improving our capacity to reliably and economically produce complex structures from nanoscale metallic building blocks. Unfortunately, the organization of large quantities of nanomaterials via ?bottom-up? strategies that are scalable, cost-effective and that achieve precise structure control is still limited. This project will research a new strategy to assemble complex structures from nanoparticle building blocks by exploiting local steric repulsion and short-ranged attraction. In this new approach, the formation of structured clusters or will be controlled through the use of engineered nanoparticle surfaces containing mixtures of end-grafted polymers to regulate steric repulsion and small functional molecules to induce attraction. Steric repulsion and attractive interactions will be precisely adjusted by altering the surface composition to control particle assembly and to manipulate the morphology of the multi-particle structures. Diverse colloidal clusters with controllable optical and electronic properties will be generated using this robust strategy. Small angle scattering of x-rays and neutrons will be used to selectively probe the nanoparticle configuration (SAXS) and the conformation of the polymers (SANS) in order to develop a complete and self-consistent description of the assembly process. Structural experiments will be complemented by direct comparisons to simulations. The primary goals of the project will be to: 1) Experimentally determine the role of polymer interactions in mediating nanoparticle self-assembly 2) Reduce the structural polydispersity of self-assembled clusters 3) Predict equilibrium cluster structures with Monte Carlo simulations and 4) Increase the structural diversity of colloidal molecules. Achieving these objectives will contribute significantly to the advancement of plasmonic applications that utilize nanoparticle clusters. Plasmonic technologies exploit the unique interactions between visible light and delocalized electron clouds in small metallic particles. For example, plasmonic effects are used to develop sensors for the rapid identification of trace amounts of chemicals and environmental contaminants in complex samples. They also advance less invasive and more effective medical diagnostic and treatments tools such as photoacoustic imaging and photothermal cancer therapy. Plasmonic approaches are also used to develop advanced solar cells that are more efficient and less expensive than current technologies. Nonetheless, the successful deployment of these and other applications requires significant advances in the scalable fabrication of nanostructures with controllable optical and electronic properties. This project will research a new approach that is suitable to fabricate large numbers of plasmonic nanomaterials while maintaining accurate structure control and with methods that are scalable, robust and versatile.