Collaborative Research: Molecular and Nanoscale Structure and Interactions of PFAS at Interfaces and Mixed Surfactant Systems

全氟烷基和多氟烷基物质(PFAS)，也被称为“永久化学品”，由于其高度的化学和热稳定性以及使固体表面不粘、稳定灭火泡沫以及与水和碳氢化合物不相容的独特能力而被广泛应用。释放到环境中，全氟辛烷磺酸会生物积累，抵抗降解，并可能造成不利的健康影响。这些因素推动了减少未来释放的全氟辛烷磺酸和封存过去所释放的全氟辛烷磺酸的举措。这个项目的目标是开发知识，支持改善水质和设计具有定制性能的功能材料，研究水溶液中以及水-空气、水-油和水-固界面上的全氟辛烷磺酸表面活性剂。该项目将发展对环境有积极影响的全氟辛烷磺酸性能的基础知识(更有效和更少地使用氟化表面活性剂、氟化表面活性剂的修复)、健康(氟碳表面活性剂如何与碳氢表面活性剂和(生物)聚合物相互作用)和技术(合理设计隔离全氟辛烷磺酸的新材料和方法，以及对产品中可能替代全氟辛烷磺酸的新化学设计的计算评估)。通过本科生参与研究和开发新的课程材料，材料设计研究与环境、健康和社会影响的耦合将被整合到科学家和工程师的外展和教育的共同努力中。全氟烷基物质和多氟烷基物质(PFAS)包括氟化表面活性剂，由于其高度的化学和热稳定性以及独特的表面改性能力而获得广泛的应用。全氟辛烷磺酸表面活性剂可以极大地抵抗环境中的降解，可以在生物上积累，并可能造成不利的健康影响。该项目是一项协调一致的计算和实验工作，旨在解决散装水和界面上全氟辛烷磺酸的分子、纳米级组织问题。研究分为三个主题：(1)PFAS与水溶液中其他分子的竞争性分子相互作用和自组装：不同PFAS的混合物，以及PFAS与碳氢表面活性剂的混合物。(2)全氟辛烷磺酸与烃类表面活性剂在水-气、水-油界面的组织和相互作用。这种对全氟辛烷磺酸界面行为的基本了解对于推动其在水基成膜泡沫(AFFF)等关键应用中的替代以及优化全氟辛烷磺酸的封存方法(如泡沫分级和曝气)至关重要。(3)与环境中全氟辛烷磺酸的命运有关的全氟辛烷磺酸的相互作用和绑定以模拟固体表面，以及用于使表面不粘的全氟辛烷磺酸的替代。该项目将产生关于含有全氟辛烷磺酸和氢化表面活性剂的体系的相互作用和自组装的新知识；对全氟辛烷磺酸在复杂的液-液、气-液和液-固界面上行为的分子尺度的洞察；以及对全氟辛烷磺酸表面活性剂在定义广泛技术应用的界面性质中的作用的深入理解。这些基础知识支持改善水质和设计具有定制特性的功能材料。将材料设计研究与环境、健康和社会影响相结合，将成为通过本科生参与研究和开发新课程材料，共同努力扩大和教育早期职业科学家和工程师的基础。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。

Per- and polyfluoroalkyl substances (PFAS), also known as “Forever Chemicals,” find a wide variety of applications because of their high chemical and thermal stability and their unique abilities to render solid surfaces non-stick, stabilize foams for firefighting, and be immiscible with both water and hydrocarbons. Released into the environment, PFAS bioaccumulate, resist degradation, and can cause adverse health effects. These factors drive initiatives to reduce future releases of PFAS and to sequester PFAS released in the past. With a goal of developing knowledge that supports improved water quality and the design of functional materials with tailored properties, this project will investigate PFAS surfactants in aqueous solutions and at water-air, water-oil, and water-solid interfaces. The project will develop fundamental knowledge on PFAS properties that can positively impact the environment (use of fluorinated surfactants more efficiently and in smaller amounts, remediation of fluorinated surfactants), health (how fluorocarbon surfactants interact with hydrocarbon surfactants and (bio)polymers), and technology (rational design of new materials and methods for sequestering PFAS, and computational evaluation of new chemical designs for potential replacements of PFAS in products). The coupling of the materials-by-design research with environmental, health, and societal impacts will be integrated into concerted efforts toward outreach and education of scientists and engineers through the engagement of undergraduate students in research and the development of new course materials.Per- and polyfluoroalkyl substances (PFAS) include fluorinated surfactants which find a wide variety of applications because of their high chemical and thermal stability and their unique ability to modify surfaces. PFAS surfactants can be extremely resistant to degradation in the environment, can bioaccumulate, and may cause adverse health effects. This project is a concerted computational and experimental effort that addresses molecular, nano-scale organization of PFAS in bulk water and at interfaces. The research is organized into three topics of study: (1) Competitive molecular interactions and self-assembly of PFAS with other molecules present in aqueous solution: mixtures of different PFAS, and mixtures of PFAS and hydrocarbon surfactants. (2) Organization and interactions between PFAS and hydrocarbon surfactants at the water-air and water-oil interfaces. Such fundamental understanding of PFAS behavior at interfaces is crucial to advance their replacement in key applications such as aqueous film-forming foams (AFFF), and to optimize PFAS sequestration methods such as foam fractionation and aeration. (3) PFAS interactions and binding to model solid surfaces that pertain to the fate of PFAS in the environment and the replacement of PFAS that are used to render surfaces non-stick. The project will generate new knowledge on interactions and self-assembly of systems containing a distribution of PFAS and hydrogenated surfactants; molecular scale insight of PFAS behavior at complex liquid-liquid, air-liquid, and liquid-solid interfaces; and advanced understanding of the role of PFAS surfactants in interfacial properties that define a wide range of technological applications. This fundamental knowledge supports improved water quality and the design of functional materials with tailored properties. The coupling of materials-by-design research with environmental, health, and societal impacts will form the basis of concerted efforts toward outreach and education of early career scientists and engineers through the engagement of undergraduate students in research and the development of new course materials.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.