Functional Patchy Nanoparticles by Interfacial Engineering

非技术摘要金属纳米颗粒通常由有机覆盖层稳定，形成有机壳层-金属核心结构。因此，材料的性质和功能在很大程度上由这两个组分决定。在材料研究部固态和材料化学计划的支持下，这项研究项目专注于开发一种有效的程序来制备一种特殊类型的纳米材料，其中有机配体以及金属成分可以以空间控制的方式独立地结合到纳米颗粒中。这为进一步操纵纳米颗粒的结构和性质提供了一种独特的方法。那不勒斯纳米粒子被用作最初的例证，类似于在两极和赤道环具有不同结构的有机/金属成分的分层那不勒斯蛋糕。这些纳米粒子可用于制备更复杂的纳米粒子材料和结构，以及用于燃料电池阴极的关键反应--氧的电催化还原。研究活动与各种教育努力紧密结合，从对包括研究生、本科生和高中生在内的不同学生研究人员的动手培训。技术摘要本研究项目的具体目标是开发基于精心设计的界面工程的有效方案，以制备那不勒斯纳米颗粒，该纳米颗粒不仅具有有机覆盖层的三片状结构，而且具有金属核心的三片状结构。这是建立在PI实验室之前在制备两亲性Janus纳米颗粒方面取得成功的基础上的。在目前的研究项目中，重点是那不勒斯纳米颗粒，它们在纳米颗粒的两极和赤道环上表现出明显不同的化学功能。同时，利用纳米粒子与金属硫酸盐络合物之间的电偶交换反应，可以将原来的单金属纳米粒子核转变为双金属甚至三金属核，第二和第三种金属也不对称地分布在纳米粒子核上。将有机覆盖层和金属核方便地和独立地操纵成隔离的贴片，可以被用于进一步和更复杂的纳米颗粒的化学功能化。这些基本的见解有望进一步促进我们对控制纳米结构材料有组织组装的一般机制的理解。

Non-Technical AbstractMetal nanoparticles are generally stabilized with an organic capping layer, forming an organic shell-metal core structure. The materials properties and functions are therefore largely determined by these two components. With support from the Solid State and Materials Chemistry Program in the Division of Materials Research, this research project is focused on the development of effective procedures for the preparation of a special class of nanoparticle materials where the organic ligands as well as the metal components may be independently incorporated into the nanoparticles in a spatially controlled manner. This provides a unique way to further manipulate the nanoparticle structures and properties. Neapolitan nanoparticles are used as the initial illustrating examples, analogous to a layered Neapolitan cake with structurally distinct organic/metal components at the two poles and at the equatorial ring. These nanoparticles may be used to prepare more complicated nanoparticle materials and structures, and for electrocatalytic reduction of oxygen, a critical reaction at fuel cell cathode. The research activities are intimately integrated with various educational efforts, from on-hands training of diverse student researchers including graduate students, undergraduate students and high-school students. Technical AbstractThe specific aim of this research project is to develop effective protocols based on deliberate interfacial engineering for the preparation of Neapolitan nanoparticles with a tri-patchy structure not only of the organic capping layers but also of the metal cores. This is built upon the prior success of the PI's laboratory in the preparation of amphiphilic Janus nanoparticles. In the present research project the focus is on Neapolitan nanoparticles that exhibit distinctly different chemical functionalities at the two poles and on the equatorial ring of the nanoparticles. Concurrently, the original monometallic nanoparticle cores may be converted to bimetallic or even trimetallic ones by taking advantage of galvanic exchange reactions between the nanoparticles and metal-thiolate complexes, with the second and third metals also distributed asymmetrically on the nanoparticle cores. The ready and independent manipulation of both the organic capping layers and the metal cores into segregated patches may be exploited for further and more complicated chemical functionalization of the nanoparticles. The fundamental insights are anticipated to further advance our understanding of the mechanisms that control the organized assembly of nanostructured materials in general.