RAFT Step-Growth Polymerization

在化学系大分子、超分子和纳米化学项目的支持下，北卡罗来纳大学教堂山分校的尤伟博士将探索一种新的聚合方法，通过一种普遍适用的工艺，可以轻松地构建具有嵌入功能的聚合物。该项目的成功将带来一种简单易行的方法来设计具有精确定义结构的功能大分子，为广泛的应用打开新的机会。教育、合作和推广是这个项目的组成部分。所有参与该项目的学员将精通有机和聚合物合成，以及各种表征。在过去的15年里，You研究小组成功地招募了代表性不足的群体的学生进行研究，并通过北卡罗来纳大学的各种教育项目为初高中学生开发和监督实验室练习。在高分子化学中，以自由基为中心的聚合几乎等同于链式生长机制。可逆加成断裂链转移聚合（RAFT）是一种重要的可控自由基聚合方法，由于其简单、多用途，通过加入链转移剂（cta）来控制自由基聚合物的聚合度（DP），因此被广泛采用。然而，由于传统RAFT的链式生长特性，这种聚合物的骨架通常只由惰性碳原子组成，而所需的功能是通过悬垂基团引入的。这与通常提供多功能杂原子骨架的分步生长聚合形成对比，后者可以很容易地将功能引入骨架中。You小组最近发现了一种独特的方法来实现RAFT步长聚合。基于已有的研究成果，本项目旨在进一步探索这一令人兴奋的新型聚合方法，主要有两个目标：(1)建立RAFT步长聚合的一般原理和机理，并扩大与其他RAFT试剂和单体家族的化学反应；(2)了解反应条件对RAFT步长聚合反应的影响。如果成功，该项目将构建重要步骤，以实现建立一种新的聚合方法的长期目标，RAFT步长聚合，用于更广泛的用途，以合成以前无法实现的新材料。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。

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Dr. Wei You of the University of North Carolina at Chapel Hill will explore a new polymerization method that will allow the facile construction of polymers with embedded functionality in their backbone through a generally applicable process. The success of this project will lead to a simple and facile methodology of designing functional macromolecules with precisely defined architectures, unlocking new opportunities for broad applications. Education, collaboration, and outreach are integral aspects of this project. All trainees involved in this project will become proficient in organic and polymer syntheses, and a variety of characterizations. For the past fifteen years, the You research group has successfully recruited students of underrepresented groups into research, and has developed and supervised laboratory exercises for middle and high-school students through various educational programs at UNC. In polymer chemistry, free radical-centered polymerizations are almost synonymous to the chain-growth mechanism. As one of the most important controlled free-radical polymerizations, Reversible-Addition Fragmentation chain Transfer (RAFT) polymerization has been widely adopted due to its simplicity and versatility of controlling the degree of polymerization (DP) of free radical polymers, enabled by the addition of chain transfer agents (CTAs) known as the RAFT agents. However, inherent to the chain-growth nature of conventional RAFT, the backbone of such polymers usually consists of only inert carbon atoms, while desired functionality is introduced through the pendent groups. This contrasts to step-growth polymerization that typically offers multifunctional heteroatom backbones, which can easily allow the introduction of functionalities into the backbone. The You group recently discovered a unique approach to achieve RAFT step-growth polymerization. Building upon significant results, this project aims to further explore this exciting new polymerization, with two objectives: (1) to establish the general principle and mechanism of RAFT step-growth polymerization and expand the expand the chemistry with other RAFT agents and monomer family; and (2) to understand the impact of reaction conditions on the RAFT step-growth polymerization. If successful, this project will construct important steps to achieve the long-term goal of establishing a new polymerization methodology, RAFT step-growth polymerization, for broader use to enable synthesis of new materials that were previously unachievable.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.