Development of Molecular Simulation Techniques for Probing Solvent Effects in Polymer Films during Solvent Vapor Annealing

非技术总结该奖项支持计算和理论研究，以模拟一种由聚合物制成的薄膜的制备方法-具有重复分子单元的长链状分子组件。聚合物广泛用于日常材料，如汽车零部件、塑料杯和食品包装，并用于高科技应用，如微电子和太阳能电池。聚合物基材料的性能可以通过调整组成分子单元的排列来针对给定的应用进行优化。这促使工业和研究实验室的材料科学家寻找能够精确控制聚合物材料中分子排列的加工技术。一种这样的处理技术是溶剂蒸气退火，其中聚合物膜暴露在溶剂蒸气中，使得溶剂分子与聚合物膜混合，从而改变聚合物-聚合物相互作用并导致特定的结果排列。这种方法使材料科学家能够获得以前无法实现的聚合物排列，从而为创造下一代材料铺平了道路。尽管这项技术的价值已被证明，但由于缺乏对该技术的基本知识，优化的通用协议尚未建立。在这个项目中，PI将开发模型和计算机模拟方法，以获得基本的了解，推进预测建模，并使溶剂蒸气退火成为一种通用、实用和可靠的方法，促进各种技术相关应用的聚合物工程，如燃料电池、光伏和纳米膜。PI还将致力于本科教育，特别是通过培训和指导本科生在她的研究实验室以及在课堂上通过她的聚合物科学和工程导论课程。作为聚合物领域许多全国性会议的组织者，她计划邀请来自全国各地的领先的计算软材料科学家，促进聚合物科学研究的传播，并激励未来一代女性科学家和领导者。TECHNICAL SUMMARY溶剂蒸气退火是一种越来越多地使用的聚合物加工方法，其中聚合物膜中的溶剂的存在增强了聚合物的流动性，改变了聚合物-聚合物和聚合物-表面的有效相互作用，并推动了形态变化。通过溶剂蒸气退火和最终的瞬时溶剂挥发，可以捕获一些在平衡状态下看不到的技术上有用的形貌。尽管这种加工技术已被证明有价值，特别是在嵌段共聚物膜中，但由于缺乏关于溶剂、基材和聚合物(S)在溶剂退火和溶剂挥发过程中复杂相互作用的基础知识，标准或通用的方案尚未建立。这种缺乏知识的部分原因是a)在现场探索这些溶剂-聚合物相互作用和溶剂介导的聚合物-聚合物相互作用的实验技术的局限性，以及因为b)在大多数聚合物的计算研究中，溶剂被隐式处理或当显式处理时，溶剂蒸气退火期间的溶剂和聚合物的动力学没有被捕捉到。为了解决这种基础知识的缺乏，这个项目的首要目标是开发新的计算方法来模拟聚合物薄膜中的溶剂蒸气退火。计算研究将揭示聚合物薄膜中溶剂诱导的形态变化背后的热力学和动力学，并为使用溶剂蒸气退火法在均聚物共混物和共轭聚合物薄膜中实现目标形态提供通用指南。通过与实验数据的比较，这些计算方法将得到验证，并为在聚合物薄膜中实现预期的目标溶剂诱导效果所需的溶剂化学和溶剂蒸汽退火条件的选择提供指导。这种基本的理解将有助于溶剂气相沉积成为一种通用、实用和可靠的方法，促进聚合物和其他软材料薄膜的设计，这些薄膜用于各种技术相关的应用，如光刻、燃料电池、光伏和纳米薄膜。在这个项目中开发的计算工具将可用于研究均聚物共混和共轭聚合物以外的其他系统，如聚合物纳米复合材料和嵌段共聚物。国际和平协会还致力于在教育和外展工作中取得卓越成绩。她将致力于本科教育，特别是在本科生为拟议工作做出贡献的过程中对他们进行培训和指导。与拟议工作相关的结果和工具也将包括在她秋季为化学工程和材料科学本科生和研究生讲授的一门聚合物科学与工程导论课程中。PI将继续她过去的广泛努力，招募和留住女学生，并指导她们在行业、大学和国家实验室担任领导职务。通过她作为各种全国性会议的组织者的角色，PI旨在邀请来自全国各地的领先的女性计算软材料科学家，促进杰出工作的传播，并激励未来几代女性科学家和领导人。

NONTECHNICAL SUMMARYThis award supports computational and theoretical research to simulate a method to fabricate films made of polymers - long chain like molecular assemblies with repeating molecular units. Polymers are used universally in every-day materials, such as automobile parts, plastic cups, and food packaging, and in high technological applications, such as microelectronics and solar cells. The properties of polymer-based materials can be optimized for a given application by tuning the arrangement of constituent molecular units. This motivates materials scientists in industry and research labs to find processing techniques that will enable precise control over the molecular arrangement within the polymer materials. One such processing technique is solvent vapor annealing, where the polymer film is exposed to a solvent vapor so that the solvent molecules mix in with the polymer film which alters the polymer-polymer interactions and leads to a particular resulting arrangement. This method has allowed materials scientists to obtain polymer arrangements that have not been possible to achieve before, thus paving a pathway for creating next generation of materials. Despite the proven value of this technique, optimized universal protocols have not been established due to a lack of fundamental knowledge about this technique. In this project, the PI will develop models and computer simulation approaches to gain fundamental understanding, advance predictive modeling, and make solvent vapor annealing a universal, practical, and reliable method facilitating the engineering of polymers for various technologically relevant applications, such as fuel cells, photovoltaics, and nanomembranes. The PI will also dedicate significant effort to undergraduate education, specifically through training and mentoring of undergraduate students in her research lab as well as in the classroom through her Introduction to Polymer Science and Engineering course. In her role as organizer of many national conferences in the area of polymers she plans to invite leading women computational soft materials scientists from around the country, facilitating the dissemination of polymer science research, as well as serving to inspire future generation of women scientists and leaders.TECHNICAL SUMMARYSolvent vapor annealing is an increasingly utilized polymer processing method where the presence of solvent within the polymer film enhances the mobility of the polymers, alters the effective polymer-polymer and polymer-surface interactions, and drives morphological changes. Through solvent vapor annealing and eventual instantaneous solvent evaporation, some technologically useful morphologies that are not seen at equilibrium can be trapped. Despite the proven value of this processing technique, especially in block copolymer films, standardized or universal protocols have not been established due to a lack of fundamental knowledge regarding the complex interplay between solvents, substrate, and polymer(s) during solvent annealing and solvent evaporation. This lack of knowledge is due in part to a) the limitations in experimental techniques for probing these solvent-polymer interactions and solvent mediated polymer-polymer interactions in situ, and because b) in most computational studies of polymers the solvent is treated implicitly or when treated explicitly the solvent and polymer dynamics during solvent vapor annealing are not captured. To address this lack of fundamental knowing the overarching goal of this project is to develop new computational approaches to simulate solvent vapor annealing in polymer films. The computational research will uncover the thermodynamics and kinetics underlying solvent-induced morphology changes within polymer thin films and provide universal guidelines on the use of solvent vapor annealing to achieve target morphologies in homopolymer blends and conjugated polymer based films. Through comparison with data from experiments these computational techniques will be validated and provide guidance on the selection of solvent chemistries and solvent vapor annealing conditions for achieving desired target solvent-induced effects in the polymer film. Such a fundamental understanding will be valuable for solvent vapor deposition to become a universal, practical, and reliable method facilitating the design of polymer and other soft materials films used in various technologically relevant applications, such as lithography, fuel cells, photovoltaics, and nanomembranes. The computational tools developed in this project will be made available for others studying systems beyond homopolymer blends and conjugated polymers, such as polymer nanocomposites and block copolymers. The PI is also committed to achieving excellence in education and outreach efforts. She will dedicate significant effort to undergraduate education, specifically via training and mentoring of undergraduate students during their contributions towards the proposed work. The results and tools pertinent to the proposed work will also be included in an Introduction to Polymer Science and Engineering course that she teaches in the fall to undergraduates and graduate students from chemical engineering and materials science. The PI will continue her extensive past efforts to recruit and retain female students and mentor them to leadership roles in industry, universities, and national laboratories. Through her role as organizer of various national conference, the PI aims to invite leading women computational soft materials scientists from around the country, facilitating the dissemination of outstanding work, as well as serving to inspire future generations of women scientists and leaders.