CAREER: Multiscale Modeling of Polymersomes

该职业奖支持关于链状分子单元或聚合物如何自行组装形成限制溶液的囊泡的理论和计算研究和教育。这种被称为聚合体的囊泡在软性材料领域有多种应用，如药物输送装置，甚至是用于化学反应的微小纳米级烧瓶。聚合物的形状可以根据温度或溶剂类型等外部刺激进行调整。PI将重点研究由一种特殊聚合物制成的聚合体，这种聚合物含有一种亲水分子单元，这种分子单元可以溶解或与水混合，它与一种不能与水混合的疏水分子单元相连。在低浓度的水中，根据聚合物的长度和亲水与疏水基团的精确比例，这些聚合物可以组装成球形、蠕虫状或囊泡状。PI将使用计算和重点研究这些聚合物的自组装成聚合体。该奖项将使用分子动力学模拟方法来研究这些聚合体的自组装及其弹性特性。在分子动力学中，原子和分子相互作用的规律在数学上用力场来描述。该奖项将创造新的力场，以模拟微米量级的大长度尺度和数百微秒量级的长时间尺度的聚合体。PI将致力于发展这些力场，以便它们准确地描述聚合体的弹性特性。此外，这些力场将用于研究如何改变聚合物改变聚合物膜的性质。此外，PI将利用分子动力学模拟的专门技术来研究膜中孔隙的形成，以及改变膜的形状。作为上述研究活动的补充，拟议的教育和外展活动包括加强史坦顿岛学院和纽约城市大学（CUNY）的当地教育和研究环境，并更紧密地将这些机构与纽约当地教师结合起来。PI与当地一位高中老师合作，这位老师是史坦顿岛学院的校友，PI开发了几个课程模块，向学生介绍化学概念。PI将测试和评估这些模块的影响。此外，PI将与纽约市立大学高性能计算中心合作，建立一个为期两天的研讨会，向当地高中教师介绍计算化学和高性能计算，名为“用计算化学教学科学研讨会”。在CSI学术评估主任的指导下，PI将通过对教师的调查来评估这次研讨会的影响，以了解它如何影响和改善课堂环境。PI在从高中到博士后阶段指导对STEM领域感兴趣的少数民族和女性方面的经验和目前的活动，都加强了拟议的研究和教育活动。该职业奖支持理论和计算研究和教育，以开发和利用多尺度计算方法，目的是推导设计原则来控制聚合体的性质。几乎所有的软质材料，特别是基于聚合物自组装的材料，都远离它们的平衡状态。这不仅是一个挑战，也是一个利用自组装的结构、形态和转化动力学来优化材料性能的机会。事实上，调节分子组装形状以响应外部刺激的能力在调整材料的热力学、力学和光子特性方面有许多应用。这项研究活动旨在开发多尺度计算方法，为指导带电聚合物膜（包括聚合体）弹性特性的设计原则提供基本见解。聚合体，特别是刺激反应聚合体，作为纳米载体、纳米反应器，甚至作为仿生系统，具有多种应用。在这个项目的范围内，PI将开发一个计算工具箱，可以用来设计具有关键物理性质的聚合体。具体来说，PI将为自组装成聚合体的常见二嵌段共聚物设计粗粒力场，并使用一系列分子动力学方法来表征和预测其弹性性能。接下来，PI将利用各种计算方法来预测这些聚合体的稳定性，特别是穿透膜所需的能量，以及表征它们在形状上的刺激响应变化。本研究项目的重点是计算方法和力场的发展，以表征两亲分子自组装的中间形态和形状转换。这些新的计算技术将得到验证和实验验证，并将允许合理设计新的二嵌段共聚物混合物，这些混合物可以自组装成聚合物形态，可以由实验合作者进行测试。新的计算方法从分子水平上为各种形态自组装的设计提供信息，同时也包含了它们动态形状转换的潜力，可以影响多个软材料领域。拟议研究的结果将允许分子设计策略，可用于定制两亲分子，以优化其对外部刺激（如溶剂或盐浓度）的动态响应。例如，本提案中讨论的二嵌段共聚物可以用于药物输送或催化活性纳米马达等应用。作为上述研究活动的补充，拟议的教育和外展活动包括加强史坦顿岛学院和纽约城市大学（CUNY）的当地教育和研究环境，并更紧密地将这些机构与纽约当地教师结合起来。PI与当地一位高中老师合作，这位老师是史坦顿岛学院的校友，PI开发了几个课程模块，向学生介绍表面活性剂胶束化等化学概念。PI将测试和评估这些模块的影响。此外，PI将与纽约市立大学高性能计算中心合作，建立一个为期两天的研讨会，向当地高中教师介绍计算化学和高性能计算，名为“用计算化学教学科学研讨会”。在CSI学术评估主任的指导下，PI将通过对教师的调查来评估这次研讨会的影响，以了解它如何影响和改善课堂环境。PI过去的经验和目前在指导对STEM领域感兴趣的少数民族和女性从高中到博士后水平的活动，都加强了拟议的研究和教育活动。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARYThis CAREER award supports theoretical and computational research and education on how chain-like molecular units, or polymers, can assemble themselves to form vesicles that confine a solution. The vesicles, called polymersomes, have diverse applications in the soft materials community as drug delivery devices or even as tiny, nanoscale, flasks for chemical reactions. The shape of the polymersome can be tailored in response to external stimuli such as temperature or type of solvent. The PI will focus on polymersomes made of a particular kind of polymer that contains a hydrophilic molecular building block, one that can dissolve or mix with water, that is connected to a hydrophobic molecular building block which does not mix well with water. At low concentrations in water, depending on the polymer length and exact ratio of hydrophobic to hydrophilic groups, these polymers can assemble into spherical shapes, worm-like shapes, or vesicle-like shapes. The PI will use computation and focus investigation on the self-assembly of these polymers into polymersomes. This award will use molecular dynamics simulation methods to investigate both the self-assembly of these polymersomes as well as their elastic properties. In molecular dynamics, the rule by which atoms and molecules interact with each other is mathematically described by a force field. This award will create new force fields to simulate polymersomes at large length-scales on the order of microns and long time-scales on the order of hundreds of microseconds. The PI will aim to develop these force fields so that they accurately describe the elastic properties of the polymersomes. In addition, these force fields will be used to investigate how adding change to the polymers changes the properties of the polymersome membrane. Furthermore, the PI will utilize specialized techniques in molecular dynamics simulation to investigate the formation of pores in the membrane, as well as change the membrane shape.Complementing the above research activities, proposed educational and outreach activities include strengthening the local educational and research environment of College of Staten Island and City University of New York (CUNY), and more closely integrating the institutions with local NY teachers. Working with a local high school teacher who is an alumna of College of Staten Island, the PI has developed several course modules that introduce students to concepts in chemistry. The PI will test and assess the impact of these modules. Moreover, the PI will establish a two- day workshop to introduce local high school teachers to computational chemistry and high-performance computing, in collaboration with the High-Performance Computing Center at CUNY, entitled Workshop for Teaching Science with Computational Chemistry. The PI will assess the impact of this workshop through surveys of the teachers after and during the next school year to see how this impacts and enhances the classroom environment, with the guidance of the Director for Academic Assessment at CSI. The proposed research and the educational activities are all enhanced by the PI's experience and current activity in mentoring minorities and females interested in the STEM fields all the way from the high school to postdoctoral level. TECHNICAL SUMMARYThis CAREER award supports theoretical and computational research and education to develop and utilize multi-scale computational methods with the aim of deducing design principles to control the properties of polymersomes. Nearly all soft materials, particularly materials based on polymeric self-assembly, are far from their equilibrium state. Not only is this a challenge, but it is also an opportunity to harness the structure, morphology, and transformation kinetics of self-assemblies to optimize materials properties. Indeed, the ability to tune molecular assembly shape in response to external stimuli has numerous applications in tailoring the thermodynamic, mechanical, and photonic properties of materials. This research activity aims to develop multi-scale computational approaches that will provide fundamental insight into the design principles guiding the elastic properties of charged polymeric membranes, including polymersomes. Polymersomes, in particular, stimuli-responsive polymersomes have diverse applications as nanocarriers, nanoreactors, and even as biomimectic systems. Within the scope of this project the PI will develop a computational toolbox that can be used to engineer polymersomes with key physical properties. Specifically, the PI will design coarse grain force fields for common diblock copolymers that self-assemble into polymersomes, and use an array of approaches in molecular dynamics to characterize and predict their elastic properties. Next, the PI will utilize various computational methodologies to predict the stability of these polymersomes, specifically the energy required to porate the membrane, as well as characterize their stimuli-responsive change in shape.A focus of this research project is the development of computational methods and force fields to characterize intermediate morphologies and shape transformations underlying molecular self-assembly of amphiphilic molecules. These new computational techniques would be both verified and experimentally validated, and would allow for the rational design of new diblock copolymer mixtures that can self-assemble into the polymersome morphology, that can be tested by experimental collaborators. New computational methods that inform the design of diverse morphological self-assemblies from the molecular level up, that also incorporate their potential for dynamic shape transformation, can impact multiple soft materials fields. Outcomes of the proposed research will allow for molecular design strategies that can be used to tailor amphiphiles to optimize their dynamic response to external stimuli such as solvent or salt concentration. For example, the diblock copolymers discussed within this proposal can be tailored for applications such as drug delivery or as catalytically active nanomotors. Complementing the above research activities, proposed educational and outreach activities include strengthening the local educational and research environment of College of Staten Island and City University of New York (CUNY), and more closely integrating the institutions with local NY teachers. Working with a local high school teacher who is an alumna of College of Staten Island, the PI has developed several course modules that introduce students to concepts in chemistry such as surfactant micellization. The PI will test and assess the impact of these modules. Moreover, the PI will establish a two-day workshop to introduce local high school teachers to computational chemistry and high-performance computing, in collaboration with the High-Performance Computing Center at CUNY, entitled Workshop for Teaching Science with Computational Chemistry. The PI will assess the impact of this workshop through surveys of the teachers after and during the next school year to see how this impacts and enhances the classroom environment, with the guidance of the Director for Academic Assessment at CSI. The proposed research and the educational activities are all enhanced by the PI's past experience and current activity in mentoring minorities and females interested in the STEM fields all the way from the high school to postdoctoral level.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.