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

非技术总结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另一种液体介质中液滴的形成，即所谓的液-液相分离。在生物学上，这导致了可以组织细胞内部的隔间。在工业中，类似的效果也被用来控制个人护理或食品的“感觉”或质地。这些相分离现象的物理原因很复杂，但通常被归因于几种类型的大分子与静电相互作用。其中许多系统包括折叠蛋白质等颗粒，这些颗粒含有纳米级的带电斑块，可以与长链、灵活的分子相互作用。PI的小组将研究这些带电粒子的表面如何影响液-液相分离。这将包括理解被称为聚阳离子的带正电的分子链和形成与肥皂中发现的类似的纳米结构的带负电的分子之间的“粘性”，称为表面活性胶束。聚阳离子和表面活性剂胶束粘在一起，形成一种动态的凝胶状材料，称为复杂凝聚体。这种粘连将高度依赖于胶束的斑驳程度，以及阻碍带电相互作用的分子的存在。PI的小组将确定不同的斑块和分子组成将如何影响液-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，并将指导工程师在寻求使用更绿色、更健康的配方时，在复杂的设计空间中导航。该项目的综合教育和外联部分支持对代表性不足的少数群体进行更广泛的外联，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大学圣埃尔莫·布雷迪STEM学院内PI设计的活动的核心。这个项目将通过开发介绍(宏观)分子及其相应材料的概念的模块，建立理解现有努力的更高级方面所需的演示。整个活动将向小学生介绍塑料的生命周期和可持续性。技术总结本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片状如何影响聚电解质/颗粒溶液中的相分离。各种各样的材料系统，从消费品到电池中的相分离区域，都依赖于电荷驱动的相分离。这种“凝聚”的过程可以由相反电荷的聚电解质和粒子物种(如表面活性剂胶束或蛋白质)之间的吸引所驱动。从生物学中获得线索，PI将确定带电相互作用和斑块如何控制PE粒子凝聚体中的相行为。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图案化之间的关系。这项研究将建立在已建立的混合场理论模型的基础上，通过基于粒子的模拟了解参数，以了解附近带电粒子之间由聚电解质介导的强烈静电。这个模型将首先用来探索空间位阻和疏水相互作用对表面活性剂-聚电解质凝聚体的影响，然后将带电图案引入到颗粒上来表示朗朗上口的颗粒或蛋白质。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体奠定理论和计算基础，为带电图案化和表面相互作用对体相行为的作用提供新的见解。这将对对广泛的消费应用和生物系统至关重要的材料产生影响。外联和教育也是这一研究项目的组成部分，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的小组将开发扩展活动，进一步将计算集成到现有的、成功的项目中，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的困难和抽象概念的参与。功绩审查状态：该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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 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.