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“Forever Chemicals”，由于其高化学和热稳定性以及其使固体表面不粘、稳定消防泡沫以及与水和碳氢化合物不混溶的独特能力，其应用范围广泛。PFAS释放到环境中后，会发生生物累积，抵抗降解，并可能对健康造成不良影响。这些因素促使采取措施，减少今后全氟辛烷磺酸的释放，并封存过去释放的全氟辛烷磺酸。为了开发支持改善水质和设计具有定制特性的功能材料的知识，该项目将研究水溶液中以及水-空气，水-油和水-固体界面的PFAS表面活性剂。该项目将开发有关PFAS特性的基本知识，这些特性可以对环境产生积极影响（更有效和更少量地使用氟化表面活性剂，氟化表面活性剂的补救），健康（碳氟表面活性剂如何与烃表面活性剂和（生物）聚合物相互作用），以及技术（合理设计新材料和螯合PFAS的方法，以及计算评估产品中PFAS潜在替代品的新化学设计）。材料设计研究与环境、健康、通过让本科生参与研究和开发新的课程材料，将把对科学家和工程师的宣传和教育以及对社会的影响纳入协调一致的努力。包括氟化表面活性剂，由于它们的高化学和热稳定性以及它们独特的表面改性能力，它们具有广泛的应用。PFAS表面活性剂对环境中的降解具有极强的抵抗力，可生物累积，并可能对健康造成不良影响。这个项目是一个协调一致的计算和实验的努力，解决分子，纳米级组织的PFAS在散装水和界面。本研究分为三个研究主题：（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与烃类表面活性剂的混合物。(2)PFAS与烃类表面活性剂在水-空气和水-油界面上的组织和相互作用。对PFAS界面行为的这种基本理解对于推进其在关键应用中的替代至关重要，例如水性成膜泡沫（AFFF），以及优化PFAS螯合方法，例如泡沫分离和曝气。(3)PFAS与模型固体表面的相互作用和结合与PFAS在环境中的命运有关，以及用于使表面不粘的PFAS的替代。该项目将产生关于包含PFAS和氢化表面活性剂分布的系统的相互作用和自组装的新知识; PFAS在复杂的液-液，气-液和液-固界面的分子尺度洞察力;以及对PFAS表面活性剂在定义广泛技术应用的界面特性中的作用的深入理解。这些基础知识有助于改善水质和设计具有定制特性的功能材料。材料设计研究与环境，健康，该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的评估来支持的。影响审查标准。

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.