Assembling Dendritic and Branched Molecules at Interfaces

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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.