CAREER: Developing the Design Rules of Charge Sequence to Inform Polymer Self-Assembly

非技术总结这个职业奖项支持理论和计算研究和教育，以阐明设计模仿生物学的聚合物材料的规则。聚合物是由连接的分子单元组成的长链状分子，称为单体。由聚合物制成的材料被广泛用于从橡皮筋到汽车塑料部件再到包装材料等广泛的常见应用。PI的灵感来自于生物系统的复杂精确度，这些生物系统由大分子组成，这些大分子使用以静电电荷模式编码的信息进行特定和唯一的相互作用。PI将调查是否可以使自组织聚合物以类似的方式工作。PI的研究小组将决定如何设计聚合物分子链上带静电的单体图案，以指导分子结构在纳米尺度上的自组织。聚合物的单体序列将成为将分子组装在一起的工具，就像拼图一样。要做到这一点，PI将考虑强吸引的聚合物体系，因为它们由称为聚阳离子的正电荷链和称为聚阴离子的负电荷链组成。在溶液中，大量的这些聚阳离子和聚阴离子粘在一起，形成一种动态的凝胶状材料，称为复杂凝聚体。这种“粘着”高度依赖于沿着聚合物主干的电荷顺序，PI的研究小组将确定不同的模式是如何从哪些聚阳离子与哪些多阴离子相互作用中产生的。这一组装主题将使需要纳米级结构精度的广泛类别的材料取得进展，如燃料电池膜、功能涂层和传感器以及药物输送车辆。该项目的综合教育和外联部分支持对代表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。推广工作包括将PI小组的计算机模拟进展放在聚合物可持续性和实验合作的背景下进行。交互式计算机模拟是伊利诺伊大学圣埃尔莫·布雷迪STEM学院内由PI设计的活动的核心。这项活动将向代表性不足的少数民族的小学生介绍塑料的生命周期和可持续性。技术总结这个职业奖项支持理论和计算研究以及寻求使用序列设计的聚合物来模拟生物大分子的教育。序列控制是解决聚合物科学中一项重大挑战的关键：设计对刺激做出反应、对信息进行编码并形成复杂结构的软材料。PI的小组将从由于电荷单体序列中编码的信息而经历特定结合的生物聚合物中获得线索，并建立利用电荷图案进行聚合物自组装所需的设计规则。在这项工作中，PI将系统地探索电荷序列如何决定相反电荷聚电解质之间的相互作用强度和特异性。这些聚合物的溶液经过缔合相分离形成复杂的凝聚体，这是将电荷图案化与宏观相行为和纳米级组装联系起来的理想模型系统。蒙特卡罗模拟和混合粒子/场模拟方法将用于探索：1)控制相互作用强度的局部单体放置和图案，以及2)通过互补序列提高相互作用特异性的等长电荷变化。这两种序列长度标尺都将为使用电荷序列编码自组装提供基础。这项研究将阐明使用序列定义的聚合物来驱动聚合物设计的原理，使用独特的模拟方法，解决将单体级别的序列与形态或宏观现象联系起来的不同长度尺度。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。外展工作包括将PI小组的模拟进展放在聚合物可持续性和实验合作的背景下进行。交互模拟是伊利诺伊大学圣埃尔莫·布雷迪STEM学院内由PI设计的活动的核心。这项活动将向代表性不足的少数民族的小学生介绍塑料的生命周期和可持续性。

NONTECHNICAL SUMMARYThis CAREER award supports theoretical and computational research and education to elucidate rules for designing polymeric materials that mimic biology. Polymers are long chain-like molecules that are made of joined molecular units called monomers. Materials made from polymers are used in a wide range of common applications from rubber bands to plastic components of automobiles to packaging materials and more. The PI is inspired by the sophisticated precision of biological systems which are made from large molecules that specifically and exclusively interact using information encoded in patterns of electrostatic charge. The PI will investigate whether polymers that self-organize can be made to behave in a similar way. The PI's group will determine how patterns of electrostatically charged monomers along a polymer molecular chain can be designed to guide the self-organization of molecular structures at the nanometer length scale. The monomer sequence of a polymer will be a tool to fit molecules together like puzzle pieces. To do this, the PI will consider polymer systems that strongly attract because they consist of chains of positive charge called polycations and chains of negative charge called polyanions. In solution, large numbers of these polycations and polyanions stick together in a dynamic, gel-like material known as a complex coacervate. This "sticking" is highly dependent on the sequence of charges along the polymer backbone, and the PI's group will establish how different patterns emerge from which polycations interact with which polyanions. This assembly motif will enable advances in a broad class of materials that demand structural precision at the nano-level, such as fuel cell membranes, functional coatings and sensors, and drug delivery vehicles.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 placing the computer simulation advances of the PI's group into the context of polymer sustainability and experimental collaboration. Interactive computer simulation is the centerpiece of a PI-designed activity within the St. Elmo Brady STEM Academy at the University of Illinois. This activity will introduce the lifecycle of plastics and sustainability to elementary-age students in underrepresented minorities. TECHNICAL SUMMARYThis CAREER award supports theoretical and computational research and education that seeks to use sequence-designed polymers to emulate biological macromolecules. Sequence control is key to addressing a grand challenge in polymer science: design soft materials that respond to stimuli, encode information, and form complex structures. The PI's group will take cues from biopolymers that undergo specific binding due to information encoded in charge monomer sequence, and establish the design rules needed to harness charge patterning for polymer self-assembly. In this work, the PI will systematically explore how charge sequence dictates the interaction strength and specificity between oppositely-charged polyelectrolytes. Solutions of these polymers undergo associative phase separation into complex coacervates, which serve as an ideal model system for connecting charge patterning to macroscopic phase behavior and nanoscale assembly. Monte Carlo simulation and hybrid particle/field simulation methods will be used to probe: 1) local monomer placement and patterns that will control interaction strength, and 2) contour-length charge variation that can promote interaction specificity via complementary sequences. Both sequence length scales will provide the basis for using charge sequence to encode self-assembly. This research will elucidate principles of using sequence-defined polymers to drive polymer design, using simulation methods uniquely suited to addressing the disparate length scales connecting monomer-level sequence to morphological or macroscopic phenomena. 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 placing the simulation advances of the PI's group into the context of polymer sustainability and experimental collaboration. Interactive simulation is the centerpiece of a PI-designed activity within the St. Elmo Brady STEM Academy at the University of Illinois. This activity will introduce the lifecycle of plastics and sustainability to elementary-age students in underrepresented minorities.