This Functional Nanotechnology award to Professors Josef Michl and John Price at the University of Colorado-Boulder and Professor Mark Ratner at Northwestern University is supported by the Advanced Materials and Processing Program in Chemistry, the Surface Engineering and Tribology Program in the Division of Civil and Mechanical Systems, the Western Europe Program in the Division of International Programs and the Office of Multidisciplinary Activities in the Mathematical and Physical Sciences Directorate. The research deals with the design, synthesis and characterization of nanometer scale surface-mounted molecular dipolar rotors and rotor arrays. The basic device will be a surface-mounted molecular dipolar rotor, whose base attaches covalently to a flat insulating surface and supports an axis mounted perpendicularly to the surface, which in turn supports a balanced 1-2 nm diameter rotor with a large in-plane electric dipole moment. The bearing, a fundamental element of molecular-scale mechanics will consist of a metal-to-pi-face bond. Both single rotors and self-assembling arrays of interacting rotors will be constructed. The size and moment of inertia of the rotor, its height above the surface, the rotational friction, the magnitude of the dipole, the spacing of the dipole array and its Curie temperature, propagation velocities and dissipation will be controlled by appropriate design of chemical structures. Rotor arrays have many potential applications as ferroelectric, piezoelectric and pyroelectric materials, and will be useful in reducing the size of voltage-tunable filters, oscillators, phase-shifters as well as sensors, actuators, delay lines and resonators. Such advances would ultimately contribute to miniaturization of RF products such as cellular handsets and wireless modems. Synergistic interactions between the participating investigators in synthesis, characterization and theory will provide a valuable, interdisciplinary learning experience for the students involved.
