The goal of this project is to explore new strategies in patterning of thin polymer film on sub-100 nm length scales. The proposed approach takes advantage of branched macromolecules that possess three characteristic properties: mesoscopic size, well-defined shape, and mechanical tension in their covalent bonds. These properties become particularly evident in branched macromolecules tethered to a substrate which enhances steric repulsion between the densely connected branches. To alleviate the confinement-induced stress, branched macromolecules may opt to either undergo orthogonal phase separation leading to intercalation of chemically different molecules or break the linker leading to molecular cavities in the film. The significant implications of these phenomena call for fundamental studies to shed light on the role of the branched architecture in micro-structuring of thin polymer films. With thin intention in mind, it is proposed to investigate two complementary systems: (i) branched macromolecules on liquid substrate and (ii) and branched macromolecules tethered to a solid substrate. One will study thermodynamics and kinetics of molecular intercalation to understand the mechanisms and the length scale of the pattern formation. The experimental studies will guide the design of branched architectures and will be used to verify the theoretical predictions for molecular conformation and microphase separation in thin films.
NON-TECHNICAL SUMMARY: This project will generate new materials and physical tools for controlling microstructure of thin polymer films on molecular length scales, which carry vital implications for microelectronics, data storage, photonics, and fuel cells. The outreach plan includes three key areas of activity: (i) nurturing prospective scientists through comprehensive participation of high-school students in research, (ii) the development of molecular imaging techniques for university and high-school classrooms, (iii) broadening participation of underrepresented groups through collaboration with the suc-SEED Project. The project will also strengthen collaboration between the chemistry departments at UNC, Carnegie Mellon University, the University of Athens, and Ecole Polytechnique Federale de Lausanne. The interdisciplinary and collaborative nature of the proposed research program provides rich opportunities for preparation of students for the competitive global economy where researchers must work together across disciplines and geographic distances, as well as organizational, cultural, and personal differences.
