Development of User-Friendly Controlled Cationic Polymerizations Under Ambient Conditions

在化学系大分子、超分子和纳米化学项目的支持下，康奈尔大学的特里斯坦·兰伯特教授将开发一种更方便使用、更通用的方法来制造一类重要的聚合物。这些聚合物是由被称为“活性阳离子聚合”的化学反应形成的，对人类有广泛的潜在应用。然而，由于这些聚合反应中的中间体具有非常活泼的性质，它们往往难以控制，并且对水等杂质高度敏感。这些缺点严重限制了这些化学物质可以制备的材料，并抑制了非专业人员的使用。因此，为活性阳离子聚合提供更大的控制和鲁棒性的策略的发展是一个具有广泛影响的重大挑战。该研究项目将开发这样一种阳离子聚合策略，使用一种新型聚合剂，称为五羧基环戊二烯，简称“PCCPs”。PCCPs具有独特的性质，使它们能够促进快速而受控的阳离子聚合，从而防止像水这样的杂质，从而使这些反应无需特别预防措施即可直接进行。PCCPs还有助于控制聚合物的分子结构，从而控制其宏观物理性质。在用户友好的条件下进行阳离子聚合的能力-即在室温下，无需严格避免水分或其他杂质-将为非专业人员开放这些工艺的使用，用于各种应用。康奈尔大学的Tristan Lambert教授将使用五羧基环戊二烯（PCCP）引发剂来开发用户友好的、可控的阳离子聚合反应。PCCP体系的独特特性将使这些通常高度敏感的反应能够发生，对聚合物的长度、分散性和战术性有更好的控制，并且对环境条件具有比以前更强的鲁棒性。该研究将描述这种行为的结构基础，并定义PCCP系统的范围和能力。除了这项科学工作之外，进一步的教育推广活动，如对高中生的讲座和家庭学校资源网站的开发，将把拟议的工作的影响从科学界扩展到普通公众。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, Professor Tristan Lambert of Cornell University will be developing a more user-friendly and versatile approach to make an important class of polymers. These polymers are formed from chemical reactions known as “living cationic polymerizations”, which have a broad array of potential applications for humanity. However, because of the very reactive nature of the intermediates in these polymerization reactions, they tend to be difficult to control and highly sensitive to impurities such as water. These drawbacks severely limit the materials that can be readily prepared by these chemistries and inhibit their use by non-specialists. Thus, the development of strategies that provide greater control and robustness for living cationic polymerizations represents a major challenge with wide ranging implications. This research program will develop such a strategy for cationic polymerizations using a novel class of polymerization agents called pentacarboxycyclopentadienes, or “PCCPs” for short. The PCCPs have unique properties that enable them to promote rapid yet controlled cationic polymerizations that protect against impurities like water, and thus make it straightforward to perform these reactions without special precautions. The PCCPs also aid in controlling the molecular structure of the polymer, and thus its macroscopic physical properties. The ability to conduct cationic polymerizations under user-friendly conditions—that is at room temperature and without rigorous avoidance of moisture or other impurities—will open up the use of these processes to non-specialists for use in a wide variety of applications.Professor Tristan Lambert of Cornell University will use pentacarboxycyclopentadienes (PCCP) initiators to develop user-friendly, controlled cationic polymerization reactions. The unique features of the PCCP system will enable these normally highly sensitive reactions to occur with greater control over polymer length, dispersity, and tacticity, and with greater robustness to ambient conditions than previously possible. The research will delineate the structural basis for this behavior and define the scope and capabilities of the PCCP system. In addition to this scientific effort, further educational outreach activities in terms of lectures to high school students and the development of a homeschool resource website will extend the impact of the proposed work beyond the scientific community to the general public.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.