Electrooptic Materials Based on Molecular Compasses and Gyroscopes

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Photonics technologies demand materials capable of manipulating the polarization, refraction, and transmission of light. This project comprises a search for photonic materials with electrooptic and dielectric functions based on the rotational dynamics of internal dipoles. Toward that end, the preparation of solids built with molecules having structures and functions that are analogous to those of macroscopic compasses and gyroscopes are viewed as a priority. While these solids have been shown to display the expected behavior, challenges remain in their preparation and on the optimization of their functions. Current goals include the preparation of structures capable of responding to alternating current fields in the mega- and terra-Hertz regimes, and their implementation in a wide range of polymeric materials, and electro-optical testing. Graduate students engaged in this research receive a thoroughly interdisciplinary training that includes complex organic synthesis and techniques for the structural and dynamic characterization of solid materials. The latter include solid state nuclear magnetic resonance, electronic spectroscopy, thermal analysis and dielectric spectroscopy. Students benefit from interactions with collaborators in the Physics, Chemical, and Electric Engineering Departments at the University of California at Los Angeles (UCLA) and elsewhere, and from a large number of academic activities within the UCLA IGERT "Materials Creation and Training Program". Three Hispanic Ph.D. students involved in this project, who are on track to receive their PhD's within the next two to four years, have an excellent record mentoring undergraduate students and will continue to do so. %%%Compasses and gyroscopes are navigational instruments found in Navy ships and communication satellites. Molecular versions of these devices are thought to provide new uses in future technologies. While compasses consist of a rigid box with a magnetized needle that points towards the field created by the Earth's magnetic north, gyroscopes possess a rapidly rotating wheel capable of reporting otherwise unsuspected changes in direction (by virtue of its angular momentum). The molecular versions of compasses and gyroscopes studied in this project have analogous properties. Molecular compasses have a reorienting "polar needle" capable of finding the strongest external field, and molecular gyroscopes have a rotating group that helps the molecule resists changes in direction. This project intends to exploit the collective behavior of millions of such molecules, put to work together in novel displays and optical computers. Large arrays of molecular compasses or molecular gyroscopes have been designed to self-assemble and act together collectively. In doing that, millions and millions of needles changing their direction in unison will be able to bend, twist and block beams of light as required for display applications and optical computers. Materials made with molecular gyroscopes will have the ability of sensing fields that change with speeds that are about 100 million-million times faster than the fastest liquid crystal displays, and about one thousand times faster than the processors of our fastest office computers. This project is co-funded by the Division of Materials Research and the Chemistry Division.***