权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Synchronizing the chemical composition of silver nanoparticle surfaces

同步银纳米粒子表面的化学成分

基本信息

批准号：
2003613
负责人：
Katherine Willets
金额：
$ 39.36万
依托单位：
Temple University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2024-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2003613&HistoricalAwards=false
关键词：
Synchronizing chemical composition silver nanoparticle

项目摘要

Non-technical Summary:Silver nanoparticles (~1 – 100 nm in size, more than 1000x smaller than the width of a human hair) are used in a wide range of applications, including antibacterial coatings, cosmetics, electronics, chemical and biological sensors, and catalysis. However, silver is a highly reactive material, particularly when shrunk down to nanoscale dimensions, and is susceptible to unwanted side reactions, such as the well-known tarnish that forms when silver jewelry or utensils are exposed to the ambient environment. These unwanted side reactions can impact the performance and reproducibility of silver nanomaterials in critical applications. Even silver nanoparticles taken from the same bottle will perform differently on day 1 vs. day 100, and there can be significant batch-to-batch heterogeneity, due to the extent and chemical nature of the reactions that have happened on the surface. The objective of this proposal is to determine whether it is possible to clean the surface of silver nanoparticles that have undergone these unwanted reactions and restore them to a more uniform, reproducible silver surface. To accomplish this, silver nanoparticles will be exposed to a variety of chemical and electrochemical conditions, and the change in their surface will be monitored by following time-dependent changes in their optical properties. By tracking the behavior of large numbers of single nanoparticles, these studies will determine specific conditions that produce a shift from significant surface heterogeneity to improved homogeneity across a nanoparticle population. The proposal will also support the training of graduate and undergraduate students, all of whom participate in community outreach with the Willets lab (including the Adventures in Silver high school chemistry lab developed by the group), as well as support the ongoing professional development efforts of the PI, which focus on improving scientific communication as well as creating a more equitable and inclusive environment within chemistry.Technical Summary:Metal nanoparticles are widely used across a number of applications, including sensing, nanomedicine, and catalysis, yet dynamic changes in their surface chemistry can affect their reproducibility. Rather than attempt to control the surface of nanoparticles during synthesis, this proposal seeks to develop strategies to synchronize the surface chemistry of nanoparticles post-synthesis, thereby creating more reproducible behaviors when integrated into devices and used in applications. To synchronize the surface chemistry across a population of silver nanoparticles, sacrificial shells will be introduced, either chemically or electrochemically, which outcompete unwanted contaminants on the surface of the nanoparticles. The shells will then be removed via electrochemical stripping, ideally recovering pristine silver surfaces. This proposal will test a variety of chemical and electrochemical shells, in order to assess their ability to improve the surface homogeneity within a nanoparticle population. To quantify the success of the approach, dark field scattering microscopy will be used to track the scattering intensity, spectral profile, and spatial origin of single nanoparticles throughout the shell growth and stripping cycle. The kinetics of single nanoparticle electrodissolution will be used as a metric to confirm the quality of the resulting silver surfaces, with fast electrodissolution indicating near-pristine silver and sluggish electrodissolution kinetics suggesting high levels of surface impurities. These studies will not only yield strategies for improving the post-synthesis/storage surface homogeneity in silver nanoparticles, which will improve reproducibility in critical applications, but will also allow for direct comparisons in how the kinetics and interfacial behaviors of nanoparticles change when exposed to various perturbations. Outreach projects introducing high school students from a local minority-serving school to silver nanoparticle synthesis and spectroscopy complement the proposed work, along with PI-led professional development activities for graduate students.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.

非技术摘要：银纳米粒子（尺寸约为 1 – 100 nm，比人类头发宽度小 1000 倍以上）具有广泛的应用，包括抗菌涂料、化妆品、电子、化学和生物传感器以及催化。然而，银是一种高反应性材料，特别是当缩小到纳米级尺寸时，并且容易发生不需要的副反应，例如当银首饰或器皿暴露于周围环境时形成的众所周知的失去光泽。这些不需要的副反应会影响银纳米材料在关键应用中的性能和再现性。即使是从同一瓶中取出的银纳米粒子，在第 1 天与第 100 天的表现也会有所不同，并且由于表面发生的反应的程度和化学性质，批次之间可能存在显着的异质性。该提案的目的是确定是否可以清洁经历了这些不需要的反应的银纳米粒子的表面，并将其恢复为更均匀、可再现的银表面。为了实现这一目标，银纳米颗粒将暴露于各种化学和电化学条件下，并且通过跟踪其光学特性随时间的变化来监测其表面的变化。通过跟踪大量单个纳米粒子的行为，这些研究将确定导致纳米粒子群从显着的表面异质性转变为改善的均匀性的特定条件。该提案还将支持研究生和本科生的培训，所有这些学生都参与 Willets 实验室（包括该集团开发的 Adventures in Silver 高中化学实验室）的社区外展活动，并支持 PI 正在进行的专业发展工作，重点是改善科学交流以及在化学领域创造一个更加公平和包容的环境。技术摘要：金属纳米颗粒广泛应用于多种应用，包括传感、纳米医学和催化，但其表面化学的动态变化会影响其再现性。该提案不是试图在合成过程中控制纳米颗粒的表面，而是寻求开发同步合成后纳米颗粒表面化学的策略，从而在集成到设备中并在应用中使用时创造更多可重复的行为。为了同步银纳米粒子群体的表面化学，将通过化学或电化学方式引入牺牲壳，这会击败纳米粒子表面上不需要的污染物。然后通过电化学剥离去除外壳，理想地恢复原始的银表面。该提案将测试各种化学和电化学壳，以评估它们改善纳米颗粒群内表面均匀性的能力。为了量化该方法的成功，将使用暗场散射显微镜来跟踪单个纳米粒子在整个壳生长和剥离周期中的散射强度、光谱轮廓和空间起源。单纳米粒子电溶解动力学将用作确认所得银表面质量的指标，快速电溶解表明接近原始的银，缓慢的电溶解动力学表明表面杂质含量高。这些研究不仅将产生改善银纳米粒子合成/存储后表面均匀性的策略，这将提高关键应用中的再现性，而且还可以直接比较纳米粒子在受到各种扰动时的动力学和界面行为如何变化。向当地少数族裔学校的高中生介绍银纳米粒子合成和光谱学的外展项目，以及 PI 主导的研究生专业发展活动，补充了拟议的工作。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。