CAREER: Glass formation in strongly interacting polymers - predictive understanding from high-throughput simulation and theory

职业：强相互作用聚合物中的玻璃形成 - 通过高通量模拟和理论进行预测性理解

• 批准号: 1554920
• 负责人: David Simmons
• 金额: $ 47.5万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2018-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1554920&HistoricalAwards=false
• 关键词: CAREER; Glass; formation; strongly; interacting

NONTECHNICAL SUMMARYThis CAREER award supports theoretical and computational research, and education on soft materials. Transformational technologies ranging from vaccines that remain viable at room temperature to flexible and stable solar cells and electronics await the development of new polymeric materials, soft materials made from long molecular chains with repeating molecular units, that push the limits of material performance. Many of the most promising materials for these new technologies derive their potential from two shared features: they solidify without forming a crystal, through a process known as the glass transition; and their molecules possess strong interactions. At the same time that these features are key to the potential of these materials, they also present a challenge to rational materials design. A fundamental understanding of the physics of the glass transition, the central determinant of the properties of these materials, is still lacking. This problem is especially acute in strongly interacting polymers, because strong interactions are resistant to standard theoretical approaches and are difficult to efficiently capture in computer simulations. As a result, it has not been possible to study molecular behavior at sufficiently long time scales and in sufficiently diverse chemistries to both unravel the fundamental physics of these materials and guide their design.This project is aimed to overcome these challenges. The PI will combine new theoretical approaches and an improved strategy for simulating glass-forming materials to establish fundamental insights and design guidelines for strongly interacting glass-forming polymers. This strategy will enable access to very long time scales and tens of thousands of chemistries to identify common aspects of the molecular physics of these materials and translate them into predictive theories for their properties. This theoretical understanding, in turn, will guide selection of molecular structures yielding unique, targeted material properties. Success of this project will contribute to accelerating the development of materials with the potential to improve human health, enable a cleaner domestic energy economy, enhance the lightness and durability of auto and aircraft components, and broaden the versatility of electronics and solar cells.This research will be integrated with educational outreach activities that will advance a Science, Technology, Engineering, and Mathematics (STEM) pipeline focused on guiding outstanding students - especially those from socioeconomically underprivileged backgrounds - into STEM careers. Specific activities will include expanding a PI-initiated effort offering paid summer-to-fall research internships to high school students, engaging of undergraduates in laboratory research, and coordinating master's degree programs to cement the transition of undergraduate students into the STEM community. TECHNICAL SUMMARYThis CAREER award supports theoretical and computational research, and education on polymer glasses. Strongly interacting polymers can exhibit extreme properties with the potential to enable societally transformational technologies, such as room-temperature preservation of vaccines in hydrogen-bonding polymer glasses and flexible solar cells and electronics stabilized by extraordinarily impermeable glassy polymer films. The dynamic, mechanical, and transport properties that determine the performance of these materials are largely controlled by the details of their glass transition, both in the glassy state where the structure frozen in at the glass transition temperature "controls" these properties and at higher temperatures where the glass formation process can dominate behavior to hundreds of Kelvin above the glass transition temperature. Rational design of these materials therefore demands a predictive understanding of glass formation in strongly interacting polymers. However, an understanding of the glass transition sufficient to guide materials design remains a grand challenge of materials science. While molecular dynamics simulations have provided a valuable tool in the study of this phenomenon, they have been unable to yield a predictive understanding of its physics because their insufficient speed prohibits simulation in the deeply supercooled regime near the glass transition and prevents simulations from spanning the large sets of systems necessary to establish comprehensive structure/property relations. This problem is especially acute in strongly interacting polymers, in which simulations are substantially slower and standard theoretical approaches based only on van der Waals interactions break down. This research project is aimed to overcome these challenges and to accomplish two strategic goals:1) Identify universal mechanistic interrelations between static and dynamic properties associated with glass formation in strongly interacting polymers, including alpha relaxation time, glass transition temperature, fragility of glass formation, glassy modulus, configurational entropy, and free volume. 2) Establish mechanism-based structure-property relations predicting the dependence of these properties on the molecular structure of strongly interacting polymers.These goals will be achieved by employing a novel efficient protocol for molecular dynamics simulation of the glass transition, developed in the PI's group, to perform simulations that access the deeply supercooled regime and span large matrices of molecular properties in strongly interacting polymers. These simulation data will be employed to establish structure/property relations covering a large range of molecular properties based on molecular-level insights. Data from these simulations will also be combined with theoretical models of glass formation to establish new mechanistic understanding and theoretical descriptions of glass formation in strongly interacting polymers. Ultimately, by combining theory with high-throughput simulations, this project will establish structure/property relations to enable theory-based design of strongly-interacting glass-forming polymers. This research will be integrated with educational outreach activities that will advance a STEM pipeline focused on guiding outstanding students - especially those from socioeconomically underprivileged backgrounds - into STEM careers. Specific activities will include expanding a PI-initiated effort offering paid summer-to-fall research internships to high school students, engaging of undergraduates in laboratory research, and coordinating master's degree programs to cement the transition of undergraduate students into the STEM community.

非技术摘要这一职业奖支持理论和计算研究以及软材料的教育。从室温下保持可行性的疫苗到柔性和稳定的太阳能电池和电子产品等待新聚合物材料的开发，这些疫苗的疫苗以及由长分子链和重复分子单元制成的柔软材料的开发，这些材料会突破材料性能的极限。这些新技术的许多最有前途的材料从两个共同的特征中获得了潜力：它们通过称为玻璃过渡的过程而在不形成晶体的情况下固化；它们的分子具有强烈的相互作用。同时，这些功能是这些材料潜力的关键，它们也对理性材料设计提出了挑战。仍然缺乏对玻璃过渡物理学的基本理解，这是这些材料特性的核心决定因素。在强烈相互作用的聚合物中，此问题尤其急切，因为强烈的相互作用对标准理论方法具有抵抗力，并且很难在计算机模拟中有效捕获。结果，不可能在足够长的时间尺度和足够多样化的化学范围内研究分子行为，以揭示这些材料的基本物理学并指导其设计。该项目旨在克服这些挑战。 PI将结合新的理论方法和改进的策略，以模拟玻璃形成材料，以建立针对强烈相互作用的玻璃形成聚合物的基本见解和设计指南。该策略将使能够进入很长的时间尺度和成千上万的化学体，以识别这些材料分子物理学的共同方面，并将其转化为其性质的预测理论。反过来，这种理论上的理解将指导分子结构的选择，这些结构产生独特的目标材料特性。该项目的成功将有助于加速材料的开发，并有可能改善人类健康，使国内能源经济更清洁，增强汽车和飞机组件的轻巧和耐用性，并扩大电子和太阳能电池的多功能性，这将与这些尤其是在科学，技术，工程学上的教育活动相结合的，并将其集成到科学，技术，工程学（工程学）上 - 弱势背景 - 进入STEM职业。具体的活动将包括扩大PI发起的努力，向高中生提供有偿夏季至上的研究实习，在实验室研究中参与本科生，并协调硕士学位课程，以巩固本科生向STEM社区的过渡。技术摘要这一职业奖支持理论和计算研究以及有关聚合物眼镜的教育。强烈相互作用的聚合物可以表现出极端的特性，具有使社会转化的技术的潜力，例如氢键聚合物玻璃杯中疫苗的室温保存以及柔性太阳能电池以及通过非凡的不可渗透的玻璃玻璃聚合物膜稳定的电子产品。确定这些材料性能的动态，机械和运输特性在很大程度上受玻璃过渡的细节控制，这既在玻璃状态下都在玻璃过渡温度“控制”这些特性和较高温度下的玻璃形成过程可以统治玻璃过渡温度上方数百个kelvin的玻璃形成过程的玻璃转变温度。因此，这些材料的合理设计需要对强烈相互作用的聚合物中玻璃形成的预测理解。但是，对足以指导材料设计的玻璃过渡的理解仍然是材料科学的巨大挑战。尽管分子动力学模拟在研究这种现象的研究中提供了一种有价值的工具，但它们无法对其物理学产生预测性的理解，因为它们的速度不足禁止在玻璃过渡附近深层过冷的态度中进行模拟，并防止模拟跨越大量系统以建立全面的结构/财产关系所需的大量系统。在强烈相互作用的聚合物中，这个问题尤其急切，其中模拟的基本较慢，并且仅基于范德华相互作用的标准理论方法破裂。 该研究项目的目的是克服这些挑战并实现两个战略目标：1）确定与玻璃形成相关的静态机理相互关系，与玻璃形成相关的强烈相互作用的聚合物（包括alpha弛豫时间，玻璃过渡温度，玻璃形成的脆弱性，玻璃模量，玻璃模量，配置索引和自由体积）。 2）建立基于机制的结构特性关系，以预测这些特性对强烈相互作用聚合物的分子结构的依赖性。这些目标将通过采用新颖的有效协议来用于对PI组开发的分子动力学模拟的新型协议，从而在PI的组中开发，以访问深层过度的超级层状型和大型跨度的分子构图，以实现强大的型号和强大的分子相互作用。这些仿真数据将用于建立基于分子级见解的大量分子特性的结构/属性关系。 这些模拟的数据还将与玻璃形成的理论模型结合使用，以建立强烈相互作用聚合物中玻璃形成的新机械理解和理论描述。最终，通过将理论与高通量模拟相结合，该项目将建立结构/财产关系，以实现基于理论的强烈相互作用的玻璃形成聚合物的设计。这项研究将与教育外展活动相结合，该活动将推进一条侧重于指导杰出学生（尤其是来自社会经济贫困背景的学生）进入STEM职业的研究。具体的活动将包括扩大PI发起的努力，向高中生提供有偿夏季至上的研究实习，在实验室研究中参与本科生，并协调硕士学位课程，以巩固本科生向STEM社区的过渡。