CAREER: SusChEM: Develop Unprecedented Chain-growth Polymerization Method to Access Structurally Defined Hyperbranched Polymers

聚合物是一种具有高分子量的大分子，在日常生活的许多方面都可以发现，它利用塑料、橡胶、树脂和泡沫。为了提供坚固耐用且价格合理的聚合物材料，聚合物化学的一个重点是开发高效廉价的聚合方法，可以制备具有精确控制结构，成分和尺寸的明确定义的聚合物。这些聚合物可以转化为特定应用的功能材料，如自修复材料、纳米复合材料、涂料、润滑剂、微电子和纳米药物。在这个由化学学部大分子、超分子和纳米化学项目资助的项目中，圣母大学的高海峰教授开发了一种简便的一锅一批聚合方法，可以制备具有高度分支结构和非常窄的尺寸分布的功能聚合物。该研究项目与一项教育计划相结合，旨在开发本科水平的聚合物课程和推广活动（包括一年一度的圣母大学软材料研讨会和科学博览会），以促进学术与工业合作，并吸引当地高中学生和教师的参与。本研究旨在开发一种概念上的新聚合方法，该方法应用铜（Cu）催化叠氮化物-炔环加成（CuAAC）聚合ABm （m大于或等于2）单体，在一个锅中形成基于聚三唑的超支化聚合物。该方法的一个重要特征是将Cu催化剂限制在每个超支化聚合物分子内。形成了链式生长聚合机制，聚合物分子量线性增加，聚合分散性随反应转化而降低。此外，线性单元中的悬空B基团有望比末端单元中的悬空B基团表现出更高的反应性，从而使超支化聚合物中的线性单元快速转化为树枝状单元，最终实现高度的支化。这些研究活动为圣母大学的研究生和本科生提供了有关有机合成、聚合物化学和各种表征技术的动手实验培训。学生们正在培养针对专家和非专业观众的演讲技巧。更广泛的教育和推广影响被放大：1)提高当前和新的高分子化学主题在本科和研究生课程中的影响，2)在当地高中讲课，提高公众对先进高分子材料和纳米技术的认识，3)组织一年一度的圣母大学高分子材料研讨会，以促进学术-工业合作，并吸引高中生和教师参加当地的科学博览会。

Polymers, a type of giant molecules with high molecular weights, are found in many facets of everyday life that utilize plastics, rubbers, resins, and foams. To provide robust and affordable polymer materials, one thrust in polymer chemistry is to develop efficient and inexpensive polymerization method that can prepare well-defined polymers with precisely controlled structures, compositions and dimensions. These polymers could be translated into functional materials for specific applications, such as self-healing materials, nanocomposites, coatings, lubricants, microelectronics and nanomedicines. In this project, funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Division of Chemistry, Professor Haifeng Gao at the University of Notre Dame develops a facile one-pot one-batch polymerization method that can prepare functional polymers with highly branched structures and very narrow size distribution. The research program is integrated with an education plan to develop undergraduate-level polymer courses and outreach activities (which including an annual Notre Dame Soft Materials Symposium and Science Fair) to stimulate academic-industrial collaboration and to engage the participation of local high school students and teachers.This research seeks to develop a conceptually new polymerization method that applies the copper (Cu)-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization of ABm (m is greater than or equal to 2) monomers to form polytriazole-based hyperbranched polymers in one pot. An important feature of this method is the confinement of the Cu catalyst within each hyperbranched polymer molecule, resulting in a chain-growth polymerization mechanism with a linear increase of polymer molecular weight and decreased polydispersity with reaction conversion. In addition, the dangling B group in the linear unit is expected to demonstrate higher reactivity than those in the terminal unit, resulting in a fast conversion of linear unit to dendritic unit in hyperbranched polymers and ultimately achieving a high degree of branching. The research activities provide hands-on laboratory training to the graduate and undergraduate students at Notre Dame in organic synthesis, polymer chemistry, and various characterization techniques. The students are developing presentation skills targeting both expert and non-expert audiences. The broader education and outreach impacts are magnified by: 1) improving the impact of current and new polymer chemistry topics in the undergraduate and graduate curriculum, 2) lecturing at local high schools to raise the public awareness of advanced polymer materials and nanotechnologies, and 3) organizing an annual Notre Dame Polymer Materials Symposium to stimulate academic-industrial collaborations and engaging the participation of high school students and teachers in a local science fair.