Assembling Dendritic and Branched Molecules at Interfaces

该项目解决了树枝状和支化分子与各种官能化核心和支化分子的界面状态，如两亲性单树枝、支化圆盘和超支化聚合物。这个项目的最终目标是了解新型树枝状和支化分子的化学结构-界面组织-界面性质的基本关系，这些分子具有不同的核心形状和对称性、支化程度和性质、可变的两亲性平衡和锚定能力。对于这样的分子，表面锚定可以发生在明确定义的单个或多个点上。这种锚定应该使分子稳定在表面上，但仍允许有足够的流动性使外壳与外部官能团形成有组织的纳米组装。对于这种组装，单树果壳的末端基团完全暴露在外部相互作用中。在进一步发展这一概念时，将通过包括新类型的分子来扩展先前探索的选择：盘状、棒状和发夹支化的两亲分子、具有锚定焦点的单枝形分子、杂臂星形聚合物、官能化超支化和有机磷树枝状大分子。这项研究将解决几个重要的问题：形状持久的核心和柔性分支的化学成分和对称性如何影响界面力的平衡？在空气-水界面和固体表面形成稳定的有序单分子膜的最佳平衡是什么？树枝状结构对表面锚定有何影响？已知的线性大分子的化学和静电驱动的自组装原理如何在复杂的分支大分子中发挥作用？更广泛的影响包括促进国际和平研究所与来自美国、法国、韩国和乌克兰的科学和工程部门的其他研究人员之间的密切合作。这项合作涉及来自亚利桑那大学、CNRS图卢兹、首尔延世大学和基辅大分子化学研究所的聚合物化学家，以及来自能源部艾姆斯实验室和橡树岭国家实验室的软物质物理学家。与工业实验室的持续合作将加强这一活动，并将为研究生带来宝贵的经验。通过密集的外部合作，拟议的研究计划将使博士生成为熟悉尖端基础和应用研究的成熟的、具有国际意识的研究人员。PI将通过与几个招聘/保留计划合作，集中精力增加攻读科学和工程高级学位的学生数量，这些计划包括“学习和赚取计划”(即，招聘新生材料学生)、新生荣誉计划、科学和工程女性计划、BS/MS计划(招收大四学生到研究生计划)和REU计划。PI将继续强调招收女性和少数族裔学生，这是他相当成功的一个领域。鉴于他的研究小组目前的组成，PI预计未来三年内毕业的学生中将有50%以上是女性。这将大大增加目前不超过工程学院学生总数15%的学生人数。

The project addresses interfacial state of dendritic and branched molecules with various functionalized cores and branches such as amphiphilic monodendrons, branched discs, and hyperbranched polymers. The ultimate goal of this project is to understand the basic relationships in chemical architecture-interfacial organization-interfacial properties of novel dendritic and branched molecules with variable shape and symmetry of cores, degree and nature of branching, variable amphiphilic balance, and anchoring ability. For such molecules, surface anchoring can occur at well-defined single or multiple points. This anchoring should stabilize molecules on a surface but still allow enough mobility for the outer shell to form organized nanoassemblies with external functional groups. For such assembly, terminal groups of monodendron shell are completely exposed to external interactions. In further developing this concept, the previously explored selection will be expanded by including new types of molecules: disc-, rod-, and hair-pin branched amphiphiles, monodendrons with anchoring focal point, hetero-armed star-polymers, functionalized hyperbranches, and phosphor-organic dendrimers. This research will address several important questions: How does the chemical composition and symmetry of shape-persistent cores and flexible branches affect the balance of interfacial forces? What is an optimal balance for the formation of stable organized monolayers at the air-water interface and a solid surface? How is surface anchoring affected by the dendritic architecture? How do principles of chemically and electrostatically-driven self-assembly known for linear macromolecules, work in complex branched macromolecules? A broader impact includes fostering an intensive partnership between the PI's group and other researchers from science and engineering departments in the U.S., France, Korea, and Ukraine. This collaboration involves polymer chemists from University of Arizona, CNRS Toulouse, Yonsei University, Seoul, and the Institute of Macromolecular Chemistry, Kiev, as well as soft matter physicists from the DOE Ames Lab and Oak Ridge National Lab. Continuing collaboration with industrial labs will enhance this activity and will bring invaluable experience for graduate students. Through intensive external collaboration, the proposed research program will enable Ph.D. students to become mature, internationally aware researchers familiar with cutting-edge basic and applied research. The PI will focus his efforts to increase the number of students pursuing advanced degrees in science and engineering by working with several recruiting/retention programs, including "Learn and Earn Program" (i.e., recruiting freshman materials students), Freshman Honors Program, Women in Science and Engineering Program, BS/MS Program (recruitment of senior students to graduate program), and REU programs. The PI will continue his emphasis on recruiting women and minority students, an area in which he has been quite successful. Given the current composition of his research group, the PI expects that more than 50% of his students graduating within next three years will be women. This will be a significant increase in representation for the group that currently does not exceed 15% of all students in the engineering college.