Collaborative Research: Next Generation Rigid Rod Polymers through Combined Computation and Experimentation

聚合物几乎影响着日常生活的方方面面——从牙刷的刷毛到保护食品的包装。聚合物的化学成分决定了它的性质，包括强度、柔韧性、可回收性等，这决定了它的应用。在这个研究项目中，凯斯西储大学的Pentzer教授和匹兹堡大学的Lambrecht教授探索了烯酮（一类未被充分利用的单体）的使用，以制备具有高机械强度和高溶解度的新型聚合物，便于加工。计算预测与合成和表征相结合，使这种新型聚合物的发现具有成本和时间效率。这个多学科项目为本科生和研究生提供研究培训，为未来一代科学和工程领域的熟练劳动力做好准备。研究小组研究了硅基烯酮的链式生长聚合（R3Si(H)C=C=O），它形成了具有可变主基和侧基的溶液可加工聚合物，表现为刚性棒聚合物（rrp）。由于硅基烯酮可以产生三种不同的聚合物主化学物质以及它们的混合物，因此在这项工作中解决的挑战是形成具有特定结构和刚性的材料。Lambrecht小组开发了计算方法，用于从第一性原理预测“合成子”对反应能量和聚合物性质的贡献；计算预测通过提出合理的修改，包括溶剂极性和反离子选择，为Pentzer实验室进行的合成提供信息。Pentzer团队评估了实验条件对聚合、合成和表征新聚合物的影响，并通过生成经验数据来验证和完善Lambrecht的计算方法，从而关闭了反馈回路。研究活动包括：1)识别与链生长聚合相关的硅基烯酮的基本反应模式；2)控制定义良好的低聚物的形成；3)分别制备每种新的聚合物化学物质并确定其性质和应用。此外，Pentzer和Lambrecht每年举办一次为期两天的研讨会，讨论如何成功地将计算和实验这两个相对孤立的研究领域结合起来。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。

Polymers impact nearly every part of daily life - from the bristles on a toothbrush to the packaging that protects food. The chemical composition of a polymer dictates its properties including strength, flexibility, recyclability, etc., which define applications. In this research project, Prof. Pentzer at Case Western Reserve University and Prof. Lambrecht at University of Pittsburgh explore the use of ketenes, a class of under-utilized monomers, for preparing novel polymers with high mechanical strength, and yet high solubility for facile processing. Computational prediction is integrated with synthesis and characterization to enable cost- and time-efficient discovery of such new polymers. This multidisciplinary project provides research training to undergraduate and graduate students, preparing the future generation of skilled workforce in science and engineering fields. The research team studies the chain growth polymerization of silyl ketenes, (R3Si(H)C=C=O), which form solution processable polymers with variable backbone and side groups that behave as rigid rod polymers (RRPs). Since silyl ketenes can yield three different polymer backbone chemistries as well as mixtures thereof, the challenge addressed in this work is formation of materials with specific structure and rigidity. The Lambrecht group develops computational approaches for predicting the contributions of "synthons" on reaction energetics and polymer properties from first principles; computational prediction informs synthesis performed in Pentzer's laboratory by proposing rational modifications, including solvent polarity and counterion choice. The Pentzer group evaluates the impact of experimental conditions on polymerization, synthesizes and characterizes new polymers, and closes the feedback loop by generating empirical data to validate and refine computational approaches of Lambrecht. The research activities include 1) identifying the fundamental reactivity patterns of silyl ketenes as relevant to chain growth polymerization, 2) controlling the formation of well-defined oligomers, and 3) preparing each of the new polymer chemistries individually and establishing their properties and applications. Further, Pentzer and Lambrecht offer annually a two-day workshop on how to successfully combine two relatively siloed areas of research- computation and experiment.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.