Order and Defects in Soft Matter Architecture

Syracuse University, Syracuse NY

Investigators

Abstract

TECHNICAL SUMMARY This award supports theoretical and computational research in contact with experiment on the interplay among order, defects and geometry in soft matter systems on curved surfaces and interfaces with a focus on crystalline, hexatic, vector and nematic order. Topological defects frequently appear even in the ground state of ordered systems on curved surfaces. Some defects are required by certain topologies such as the sphere and others form to lower the total energy of the system. Defect regions are natural places for biological activity, chemical linking, unusual elastic response and aggregation of disorder. This project will develop a thorough understanding of the preferred types of defect configurations for crystalline, hexatic, vector and nematic order on a variety of curved surfaces. This will pave the way for the first-principles design of entire libraries of mesoscale components (mesoatoms) that could serve as the building blocks of novel mesomolecules or bulk materials via self-assembly or controlled fabrication. A suite of tools from the fields of geometry, topology, statistical mechanics and computational science will be employed in this investigation which will be closely coupled with experimental groups. The techniques and tools developed in the course of the proposed research, including methods of analysis, simulation applets, and databases, would be made freely available to researchers across disciplines. The PI plans to involve undergraduates, graduate students and postdoctoral associates in his research program. A particular effort will be made to recruit and retain Physics majors, particularly women, by involving them in soft condensed matter research projects. The PI also plans to bring his research into the classroom through a new Soft Matter undergraduate and to the wider community through public lectures in the Saturday Morning Physics program and the Syracuse chapter of Cafe Scientifique as well as visits to local K-12 schools. Demonstrations of soap bubble arrays on curved surfaces developed as research projects can be used in both the classroom and public lectures. NON-TECHNICAL SUMMARY This award supports theoretical and computational research and education in contact with experiments that lies at the intersection of condensed matter physics, mathematics, and biology. The PI will study how particles organize themselves on curved surfaces and at the interfaces between two materials or media. For example, experiment has been able to place small particles with an electrostatic charge on the spherical surface of a water droplet suspended in oil. The particles attempt to organize themselves in a regular geometric pattern. But because they are on a sphere rather than a flat surface, ?scars? form where the ordered array on one side does not match up with that on the other. As shown by the PI, theory is at least able to make useful predictions about features of the self-organized system. The PI will study a wider variety of systems with an aim to understand the ?scars? or defects in ordering that emerge and how geometry might be used to control how particles self-assemble into desired structures. The structure of the protein coat on a virus is another example of interest to the PI. In this case, molecules might preferentially bind to areas where there are defects on curved surface of the virus protein coat suggesting strategies for drug development. The general challenging problem of how interacting particles arrange themselves on curved surfaces has been of general interest in the field of mathematics. The techniques and tools developed in the course of the proposed research, including methods of analysis, simulation applets, and databases, would be made freely available to researchers across disciplines. The PI plans to involve undergraduates, graduate students and postdoctoral associates in his research program. A particular effort will be made to recruit and retain Physics majors, particularly women, by involving them in soft condensed matter research projects. The PI also plans to bring his research into the classroom through a new Soft Matter undergraduate and to the wider community through public lectures in the Saturday Morning Physics program and the Syracuse chapter of Cafe Scientifique as well as visits to local K-12 schools. Demonstrations of soap bubble arrays on curved surfaces developed as research projects can be used in both the classroom and public lectures.