RUI: Plasmonic Nanoparticle Sandwiches: Using Peptoid Nanosheets as Platforms for Free-Standing Nanoparticle Arrays

在化学系大分子、超分子和纳米化学(MSN)以及化学测量和成像(CMI)项目的支持下，联合学院的Ellen Robertson和她的学生正在开发制备包含金和银纳米颗粒的二维(2D)分子纳米片的方法。金和银纳米颗粒的二维阵列是检测水中疏水污染物的很有前途的传感器，但关键是：1)阵列在水中保持稳定；2)阵列中颗粒的堆积排列是可控的。罗伯逊博士和她的学生正在利用油-水界面作为平台，指导纳米颗粒在两个高度水稳定性的薄分子层之间的组装。罗伯逊研究小组的发现可能会导致开发能够检测水中低水平疏水污染物的传感器。该项目将帮助联合学院的本科生为STEM(科学、技术、工程和数学)的职业和/或研究生学习做准备，方法是每年为3-5名本科生提供实践研究机会，特别强调增加在STEM中代表性不足的群体的参与；通过在联合学院罗伯逊实验室与一所R1机构之间建立合作，使本科生能够在研究生实验室环境中工作；通过将研究纳入联合学院的纳米技术课程，吸引更多的学生。罗伯逊实验室用来生产水稳定的2D纳米颗粒阵列的特定分子层由两亲性类肽聚合物组成，这是一种相对较新的类肽药物。这些聚合物通过流体界面上涉及单层组装和坍塌的机制形成了水稳定的双层类肽纳米片。当在油水界面进行时，分散在油相中的疏水功能化纳米颗粒被结合到类肽纳米片状疏水内部。通过改变用于纳米片合成的纳米颗粒的性质(即浓度、配体、核尺寸和材料)，Robertson博士和她的学生的目标是控制包埋在金和银纳米颗粒中的纳米片的结构和光电性质。合成条件的影响将通过各种表征技术进行评估，包括紫外可见光谱、拉曼显微镜、光学显微镜、扫描电子显微镜、透射电子显微镜和原子力显微镜。具有良好光电性能的纳米片将被测试其作为表面增强拉曼散射(SERS)传感器的能力，以检测水中的疏水污染物，如多氯联苯。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Macromolecular, Supramolecular and Nanochemistry (MSN) and Chemical Measurement and Imaging (CMI) programs in the Division of Chemistry, Ellen Robertson and her students at Union College are developing methods to prepare two dimensional (2D) molecular nanosheets that incorporate gold and silver nanoparticles. Two-dimensional arrays of gold and silver nanoparticles are promising sensors for detecting hydrophobic pollutants in water, but it is critical that: 1) the arrays remain stable in water; and 2) that the packing arrangement of the particles within the arrays is controllable. Dr. Robertson and her students are using the oil-water interface as a platform to direct the assembly of nanoparticles between two thin molecular layers that are highly water-stable. The discoveries of the Robertson research team could lead to the development of sensors capable of detecting low levels of hydrophobic pollutants in water. This project will help prepare undergraduates at Union for careers and/or graduate studies in STEM (science, technology, engineering and mathematics) by providing hands-on research opportunities for three to five undergraduates each year, with an intentional emphasis on increasing participation of groups underrepresented in STEM; by establishing a collaboration between the Robertson lab at Union College with an R1 institution, enabling undergraduate students to work in a graduate lab setting; and by integrating the research into Union College’s nanotechnology curriculum, engaging a greater number of students. The specific molecular layers that the Robertson lab uses to produce water-stable 2D nanoparticle arrays are composed of amphiphilic peptoid polymers, a relatively new class of peptidomimetics. These polymers form water-stable bilayer peptoid nanosheets through a mechanism at fluid interfaces that involves monolayer assembly and collapse. When carried out at the oil-water interface, hydrophobically functionalized nanoparticles dispersed in the oil phase are incorporated into the peptoid nanosheet hydrophobic interior. By varying the properties of the nanoparticles used in the nanosheet synthesis (i.e., concentration, ligand, core size, and material), Dr. Robertson and her students aim to control the structural and opto-electronic properties of the gold and silver nanoparticle-embedded nanosheets. The effects of the synthesis conditions will be assessed through a variety of characterization techniques, including UV-visible spectroscopy, Raman microscopy, light microscopy, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Nanosheets with promising opto-electronic properties will be tested for their ability to serve as surface enhanced Raman scattering (SERS) sensors to detect hydrophobic pollutants, such as polychlorinated biphenyls, in water.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.