The goal of this project is to demonstrate the feasibility of using of acoustic fields for three-dimensional manipulation (3-D) of a nanoparticle in the air. An acoustic field generated by solid state acoustic transducers will provide a non-contact means of delivering a mechanical force to the particle, and by controlling the distribution of the force in space one will control the 3-D position of the particle. Features such as levitation and horizontal and rotational motions will be studied under different operating conditions. Experimental and theoretical efforts leading to understanding the physical mechanisms of operation of an Acoustic Tweezer for Nanoparticle Manipulator (ATNM) will be undertaken. The work proposed falls into three broad activities: device development, theoretical modeling and the concept validation. These three areas are not mutually exclusive and will proceed simultaneously. Device development includes design, fabrication and testing of acoustic transducers and accompanying electronics for efficient generation of interfacial forces. Theoretical models describing the interaction of a particle with the surface of a transducer will incorporate the nanoscale complexity of the system and the multiple length scales of the systems to be studied. These developments will be validated using dedicated measurement techniques in which various aspects created by particle size and interfacial forces will be examined in carefully controlled or simulated experimental conditions. Finally, the measured ATNM characteristics will be correlated with standard optical (micron-size particles), Atomic Force Microscope (AFM) and Near Field Optical Microscope (NSOM) (nanoparticles) techniques. The acoustic manipulation technique, once developed, will be complementary to current micro- and nano-particle manipulation techniques, such as laser tweezers, magnetic tweezers and scanning probe microscopes. In particular, this technique will provide an efficient method for separating nanoparticles according to their size, shape or interaction properties. The acoustic manipulation technique will be effective on nanoparticles regardless of their optical, electrical and magnetic properties, and thus can be used in various environments and in different media. These unique features of the acoustic manipulation technique will significantly impact the fields of characterization and application of nanoparticles. The long-term objective of this research is to develop an ATNM chip capable of autonomous and programmable manipulation of nanoparticles in gases and liquids. ATNM chip will provide an experimental platform for designing and monitoring various bio-chemical and bio-physical processes involving inorganic nanoparticles as well biological objects such as proteins or cells.
