A Nonlinear Optical Approach to Patchy Particles

技术概述：该计划由固态和材料化学计划支持，旨在展示一种新的“片状粒子”，即表面带有离散相互作用位点的颗粒，这些相互作用位点吸引或排斥其他颗粒上的互补位点-目的是指导高精度和高产量的复杂结构的自组装。这项技术本质上是光学的，依靠金属纳米颗粒中等离子体共振的倾向，将入射光集中到非常小的体积中，在那里电磁场得到极大增强。这些体积被称为热点，位于粒子上或粒子之间的尖锐角落或狭窄缝隙中。该项目将使用光反应连接物来引导更多的粒子专门结合在热点上，以便能够以类似于传统化学的方式制造胶体分子，但使用纳米粒子而不是原子。这类结构的两个简单例子是哑铃形，其中两个球形粒子连接到中心杆状粒子的两端，以及三棱镜，其中每个角落都连接着一个球体。由于该方法可以迭代使用，因此也可能出现更复杂的结构，如支链或树枝。由于可制造的银和金纳米粒子的种类繁多且增长迅速，以及可用的光反应化合物的种类繁多，该项目将代表着片状粒子自组装范例中可行的结构的数量和种类的显著增加。非-技术概述：现在有可能以大量的多样性和精确度在纳米尺度上创建粒子和结构。下一个巨大的挑战是将这些积木组装成更复杂的有序结构，结合不同的几何形状和材料。该项目开发了一种可行的新方法，使用由银和金制成的纳米颗粒作为中心构建块。它的成功将对基础科学和生物医学和纳米电子学等应用领域产生影响，因此将有助于保持美国在这些技术和经济重要领域的领先地位。该项目还将帮助培养下一代博士水平的工作者，准备在科学和工程前沿的跨学科项目中担任领导职位。

TECHNICAL SUMMARY:This program, supported by the Solid State and Materials Chemistry program, aims to demonstrate a new class of "patchy particles", particles where the surface is patterned with discrete interaction sites that attract or repel complementary sites on other particles - for the purposes of guiding the self-assembly of complex structures with high precision and yield. The technique is optical in nature and relies on the propensity of the plasmonic resonances in metal nanoparticles to concentrate incident light into very small volumes where the electromagnetic field is greatly enhanced. These volumes, known as ?hotspots?, are located at sharp corner or narrow gaps on or between particles. The project will use photoreactive linkers to guide additional particles to bind exclusively at the hotspots so that colloidal molecules can be fabricated in a manner analogous to conventional chemistry, but with nanoparticles instead of atoms. Two simple examples of such structures are a dumbbell shape where two spherical particles are attached to each end of a central rod-shaped particle and a triangular prism where a sphere is attached at each corner. Since the method can be used iteratively, significantly more complex structures, such as branched chains or dendrites, are also possible. Because of the large and rapidly growing variety of silver and gold nanoparticles that can be fabricated, and the numerous types of available photoreactive compounds , this project would represent a significant increase in the number and variety of structures that are feasible within the patchy particle self-assembly paradigm.NON-TECHNICAL SUMMARY:It is now possible to create particles and structures at the nanometer scale with a great deal of variety and precision. The next great challenge is to assemble these building blocks into more complex ordered structures combining different geometries and materials. This project develops an enabling new method using nanoparticles made of silver and gold as the central building blocks. Its success will have implications both for fundamental science and for applied fields such as biomedicine and nanoelectronics, and will therefore help maintain American leadership is these technologically and economically important fields. The project will also help educate the next generation of Ph.D. level workers ready to take leadership positions in interdisciplinary projects at the forefront of science and engineering.