UNS: Predicting the Interfacial Activity of Complex Grafted Nanoparticles

UNS：预测复杂接枝纳米粒子的界面活性

• 批准号: 1510635
• 负责人: Robert Riggleman
• 金额: $ 33.72万
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1510635&HistoricalAwards=false
• 关键词: UNS; Predicting; Interfacial; Activity; Complex; UNS; Predicting; Interfacial; Activity; Complex

#1510635Riggleman, Robert A. Numerous consumer products ranging from cosmetics, detergents, and fluids for oil recovery require the stabilization of two immiscible fluids (e.g., oils and water) as an emulsion, where one phase (typically the oil) is dispersed as stable droplets in the second phase (water). Recently, experiments have shown that adding nanometer-sized particles that have polymer chains grafted to their surface is an unusually effective and inexpensive method for stabilizing these emulsions, but the mechanism for stabilization remains poorly understood. The research goal of this proposal is to study the effect of the chemistry of the grafted polymer chains on the interfacial properties of grafted nanoparticles. We will study the conformations of the polymer brush on isolated nanoparticles, the interactions of multiple nanoparticles, including their effect on the interfacial tension and self-assembly at the interface, and we will study the effect of having charges on the grafted polymer chains. These calculations are enabled by recent simulation techniques developed in our group. Our educational goals include the training of graduate students in polymer science and engineering, and state-of-the-art simulation techniques. We will continue our group's effort at involving undergraduate and high school students in our research. Finally, we will impact the broader scientific community by developing and publishing simulation codes that perform our calculations.In recent years, there has been a growing interest in the thermodynamics of nanoparticles functionalized with polymers for use in applications such as separations membranes and oil extraction fluids. By carefully tuning the interactions between the particle cores, the grafted chains, and any components that make up the host matrix of the grafted particles, one can easily control optical and mechanical properties simply by controlling the aggregation and dispersion state of the polymer. Very recently, experiments have shown that grafted nanoparticles exhibit a remarkable interfacial activity in oil and water emulsions, and they are highly effective at stabilizing the emulsions over long periods of time at surprisingly low concentrations. Furthermore, the effect of the grafting architecture has not been explored at all; recent advances in synthetic chemistry enables grafting diblock polymers, a mixture of homopolymers, or patchy (Janus) grafting on the surface of nanoparticles. This large parameter space available to experimentalists creates a need for molecular modeling that can guide experiments toward systems that show the most promise for various applications. The goal of this proposal is to use a field theoretic simulations framework recently developed by my group to examine the structure and interfacial properties of complex grafted nanoparticles. We will examine mixed brushes, diblock polymer brushes, and Janus brushes on the surface of nanoparticles as a function of the particle core size, grafting density, brush composition, and interactions with the matrix phases. Finally, we will examine how the picture changes when one of the polymers carries a charge, while incorporating the effects of ion solvation and dielectric mismatch between the two phases creating the interface. Overall, we expect our results to have a significant impact on the design of future experiments. Our efforts will have a broad impact to society by providing fundamental insights into the design of fluids for oil extraction and a wide variety of consumer products. In addition to the doctoral students trained in polymer physics and state-of-the-art molecular modeling techniques, our work has a substantial education and outreach component involving undergraduate (and potentially high school student) research, course development, and outreach to the scientific community in general. Our lab has one undergraduate student currently working with us who has co-authored a paper, and in the summer of 2014 we had a local high school student visit our lab, performing molecular dynamics simulations of polymer melts. We are developing course modules both for specialized molecular modeling courses as well as broad first-year statistical mechanics courses that introduce and develop the field theoretic simulations framework. Finally, in addition to the standard conference meetings promoting our work, we are developing a code base that we can publish and freely release to the public. Our hope is to broaden the application and use of the field theoretic simulations framework, and we believe this can be most effectively achieved by lowering the barrier to entry. Making our codes widely available is a key part of that vision.

＃1510635Riggleman，RobertA。许多消费产品从化妆品，清洁剂和油回收的液体均需要稳定两种不混溶的液体（例如，石油和水）作为乳液，其中一种阶段（通常是油（通常是油）作为稳定的液滴，在第二阶段（水）。最近，实验表明，添加将聚合物链移植到其表面的纳米尺寸颗粒是一种异常有效且廉价的稳定这些乳液的方法，但是稳定的机制仍然很少了解。该提案的研究目的是研究移植聚合物链化学对移植纳米颗粒的界面特性的影响。我们将研究聚合物刷在分离的纳米颗粒上的构象，多个纳米颗粒的相互作用，包括它们对界面界面张力和自组装的影响，我们将研究对接枝聚合物链的电荷的影响。这些计算是通过我们小组中开发的最新仿真技术启用的。我们的教育目标包括培训聚合物科学和工程学的研究生以及最先进的模拟技术。我们将继续努力使本科生和高中生参与我们的研究。最后，我们将通过制定和发布执行我们计算的模拟代码来影响更广泛的科学界。近年来，人们对与聚合物一起功能化的纳米颗粒的热力学越来越感兴趣，可用于分离膜和油萃取液。通过仔细调整粒子芯，移植链以及构成移植粒子宿主基质的任何组件之间的相互作用，人们只需通过控制聚合物的聚集和分散状态即可轻松控制光学和机械性能。最近，实验表明，嫁接的纳米颗粒在油和水乳液中表现出显着的界面活性，并且它们在长时间以惊人的低浓度下长时间稳定乳液方面非常有效。此外，根本没有探索嫁接建筑的效果。合成化学的最新进展使植入二嵌段聚合物，均聚物或斑点（Janus）在纳米颗粒表面上移植的混合物。实验者可用的大型参数空间创造了对分子建模的需求，可以指导实验对各种应用显示最有望的系统。该提案的目的是使用我小组最近开发的现场理论模拟框架来检查复杂移植的纳米颗粒的结构和界面特性。我们将检查纳米颗粒表面上的混合刷子，二嵌段聚合物刷和Janus刷，这是粒子核心尺寸，嫁接密度，刷子组成以及与基质相的相互作用的函数。最后，我们将研究当一个聚合物携带电荷时，图片如何变化，同时将离子溶剂化和介电不匹配的效果纳入两个阶段之间的效果。总体而言，我们预计我们的结果会对未来实验的设计产生重大影响。我们的努力将对社会产生广泛的影响，通过提供针对石油提取和各种消费产品的流体设计的基本见解。除了接受聚合物物理学和最先进的分子建模技术培训的博士生外，我们的工作还具有实质性的教育和宣传成分，包括本科生（以及潜在的高中生）研究，课程发展以及对科学界的宣传。我们的实验室有一名本科生目前与我们共同撰写论文的本科生，2014年夏天，我们有一个当地的高中生参观我们的实验室，对聚合物融化的分子动力学模拟进行了分子动力学模拟。我们正在为专业分子建模课程以及广泛的一年级统计力学课程开发课程模块，介绍和开发现场理论模拟框架。最后，除了促进我们的工作的标准会议会议外，我们还开发了一个可以发布并自由发布给公众的代码基础。我们的希望是扩大现场理论模拟框架的应用和使用，我们认为这可以通过降低进入障碍来最有效地实现。使我们的代码广泛可用是该愿景的关键部分。