Charge Patterning and Molecular Interactions in the Phase Behavior of Polyelectrolyte/Particle Solutions

该奖项支持聚合物物理、热力学和复杂系统的计算机模拟领域的理论和计算研究和教育。消费产品和细胞内的生物结构都依赖于在另一种液体介质中形成液滴，称为“液-液相分离”。在生物学中，这导致了可以组织细胞内部的隔室。在工业中，类似的效果被用来控制个人护理品或食品的“感觉”或质地。这些相分离现象的物理原因很复杂，但通常归因于几种与静电荷相互作用的大分子。许多这样的系统包括折叠蛋白质等粒子，其中包含纳米级的带电斑块，与长链柔性分子相互作用。PI的团队将研究这些带电粒子的表面如何影响液-液相分离。这将包括理解带正电的分子链（称为聚阳离子）和带负电的分子（形成类似于肥皂中的纳米级结构，称为表面活性剂胶束）之间的“粘性”。聚合体和表面活性剂胶束粘在一起，形成一种动态的凝胶状物质，称为复杂凝聚体。这种粘附将高度依赖于胶束的斑块，以及阻碍带电相互作用的分子的存在。PI的团队将确定不同的贴片和分子成分将如何影响进行液-液相分离的倾向。这项工作将展示复杂的生物系统，如片状蛋白质，如何在细胞中形成类似的结构。这项工作还将为洗发水、化妆品和香水等消费品的设计提供信息，并将指导工程师在复杂的设计空间中寻找更环保、更健康的配方。该项目的综合教育和外联部分支持向代表性不足的少数群体提供更广泛的外联服务，以及研究生和本科生的研究培训和指导。推广工作包括使用交互式计算机模拟作为伊利诺伊州大学圣埃尔莫·布雷迪STEM学院pi设计活动的核心。该项目将通过开发引入（宏观）分子及其相应材料概念的模块，建立所需的演示，以了解现有工作的更“高级”方面。整个活动将向小学生介绍塑料的生命周期和可持续性。该项目将使用模拟和聚合物场理论来研究分子相互作用和电荷斑块如何影响聚电解质/颗粒溶液中的相分离。从消费产品到电池中的相分离区域，各种各样的材料系统都依赖于电荷驱动的相分离。这种“凝聚”过程可以由带相反电荷的聚电解质和颗粒（如表面活性剂胶束或蛋白质）之间的吸引力驱动。以生物学为线索，PI将建立带电相互作用和斑块如何控制pe粒子凝聚中的相行为。在这项工作中，PI将系统地研究分子结构，粒子构型和非均匀电荷模式之间的关系。这项研究将建立在一个已建立的混合场理论模型上，通过基于粒子的模拟来获得参数，以了解附近带电粒子之间由聚电解质介导的强静电。该模型将首先用于探测空间排斥和疏水相互作用对表面活性剂-聚电解质凝聚的影响，然后将带电模式引入到粒子上，以表示引人注目的粒子或蛋白质。该项目将为理解聚电解质和各种非柔性聚合物颗粒之间形成的凝聚奠定理论和计算基础，对带电模式和表面相互作用在体相行为中的作用产生新的见解。这将对广泛的消费应用和生物系统的重要材料产生影响。推广和教育也是该研究项目的一个组成部分，该项目将支持至少一名研究生和一名本科生研究人员的跨学科培训。PI的小组将开展外展活动，进一步将计算整合到现有的成功项目中，如圣埃尔莫·布雷迪STEM学院。目标是设计交互式计算活动，以增加学生对塑料生命周期和回收中困难和抽象概念的参与。优秀评审声明：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评审标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARYThis award supports theoretical and computational research and education in the fields of polymer physics, thermodynamics, and computer simulations of complex systems. Consumer products and biological structures within the cell both rely on the formation of liquid droplets within another liquid media, known as 'liquid-liquid phase separation'. In biology, this leads to compartments that can organize the interior of the cell. In industry, a similar effect is used to control the 'feel' or texture of personal care or food products. The physical reason for these phase separation phenomena is complicated, but is often attributed to several types of large molecules that interact with electrostatic charge. Many of these systems include particles such as folded proteins, which contain nanometer-scale charged patches that interact with long-chain, flexible molecules. The PI's group will investigate how the surface of these charged particles affects liquid-liquid phase separation. This will consist of understanding the 'stickiness' between positively-charged molecular chains called polycations, and negatively-charged molecules that form nanoscale structures similar to those found in soap, called surfactant micelles. The polycations and surfactant micelles stick together in a dynamic, gel-like material known as a complex coacervate. This sticking will be highly dependent on the patchiness of the micelles, and the presence of molecules that get in the way of the charged interactions. The PI's group will establish how different patches and molecular components will affect the propensity to undergo liquid-liquid phase separation. This work will show how complicated biological systems, such as patchy proteins, can form similar structures in the cell. This work will also inform the design of consumer products, such as shampoo, cosmetics, and perfumes, and will guide engineers in navigating a complicated design space as they seek to use greener and healthier formulations. The integrated education and outreach component of this project supports broader outreach to underrepresented minority groups, along with graduate and undergraduate research training and mentorship. Outreach efforts consist of using interactive computer simulation as the centerpiece of a PI-designed activity within the St. Elmo Brady STEM Academy at the University of Illinois. This project will build up demonstrations needed to understand more 'advanced' aspects of existing efforts, by developing modules that introduce the concepts of (macro)molecules and their corresponding materials. The overall activity will introduce the lifecycle of plastics and sustainability to elementary-age students. TECHNICAL SUMMARYThis project will use simulation and polymer field theory to study how molecular interactions and charge patchiness affect phase separation in polyelectrolyte/particle solutions. A wide variety of materials systems, from consumer products to phase-separated regions in the cell, rely on charge-driven phase separation. This process of 'coacervation' can be driven by the attraction between oppositely-charged polyelectrolytes and particle species such as surfactant micelles or proteins. Taking cues from biology, the PI will establish how charged interactions and patchiness control phase behavior in PE-particle coacervates. In this work, the PI will systematically study the relationship between molecular structure, particle configuration, and non-uniform charge patterning. This investigation will build on an established hybrid field theory model, with parameters informed by particle-based simulations to understand the strong, polyelectrolyte-mediated electrostatics between nearby charged particles. This model will be used to first probe the effect of steric repulsion and hydrophobic interactions on surfactant-polyelectrolyte coacervates, and then charged patterns will be introduced onto particles to represent catchy particles or proteins. This project will establish the theoretical and computational basis for understanding coacervates formed between polyelectrolytes and a variety of particles that are not flexible polymers, yielding new insights into the role of charged patterning and surface interactions on bulk phase behavior. This will have impact on materials important for a wide range of consumer applications and biological systems. Outreach and education are also an integral part of this research project, which will support the interdisciplinary training of at least one graduate and one undergraduate researchers. The PI's group will develop outreach activities, further integrating computation into existing, successful programs such as the St. Elmo Brady STEM Academy. The goal will be to design interactive computational activities to increase student engagement with difficult and abstract concepts in plastic life cycles and recycling.STATEMENT OF MERIT REVIEW: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.