The focus of the proposed research is to investigate the fundamentals of the interactions between two nanoscale structures that are placed close to each other while a fluid is flowing around them. When one of these structure oscillates, the other can be synchronized and also oscillate. Investigating this process can have applications for the design of nanoscale devices of diverse use.
The objectives of this proposal are: i) to study the fundamentals of hydrodynamic coupling between high-frequency nanoscale oscillators; and ii) to determine whether or not such oscillators can be synchronized hydrodynamically. The underlying premise is straightforward: a solid body oscillating in a fluid generates an oscillatory velocity field, which subsequently exerts an oscillatory force on a nearby body; and vice versa. At the high-frequency limit, however, the fluid dynamics of this problem becomes complex because of phase lags, the interplay between potential and viscous components of the flow, and the hydrodynamic added masses. The proposed study is primarily experimental and will rely on nanomechanical cantilevers. The first part of the study aims to develop a physical understanding of coupled hydrodynamics of nanocantilevers oscillating in water. This will be accomplished by measuring the hydrodynamic forces between nanocantilevers using elaborate optical and electronic techniques. In the second part, the nanocantilevers will be turned into independent oscillators via feedback, and the experiments will elucidate the hydrodynamic conditions under which these two autonomous oscillators will synchronize. Simple physical models, guided by the experiments, will be developed. Synchronization is a complex phenomenon, which can enable nanodevice arrays, if properly implemented. By employing synchronized arrays of nanomechanical sensors, one can increase the sensitivity and efficiency of utilizing nanooscillators as sensors. These devices can find applications in biomedical sciences, healthcare, homeland security and environmental monitoring, providing unprecedented sensitivities at the level of single molecules. The education and outreach objectives can be summarized as follows: i) recruitment of minorities to participate in the exciting and rapidly expanding field of nanofluidics; ii) outreach to high school students to encourage future careers in science and engineering; iii) course development at the undergraduate level to encourage freshmen to pursue majors in science and engineering; iv) graduate student education through state-of-the-art research and courses