title: Artificial Swimmers Propelled by Acoustically Activated Flagella.
abstract: Recent studies have garnered considerable interest in the field of propulsion to maneuver micro- and nanosized objects. Acoustics provide an alternate and attractive method to generate propulsion. To date, most acoustic-based swimmers do not use structural resonances, and their motion is determined by a combination of bulk acoustic streaming and a standing-wave field. The resultant field is intrinsically dependent on the boundaries of their resonating chambers. Though acoustic based propulsion is appealing in biological contexts, existing swimmers are less efficient, especially when operating in vivo, since no predictable standing-wave can be established in a human body. Here we describe a new class of nanoswimmer propelled by the small-amplitude oscillation of a flagellum-like flexible tail in standing and, more importantly, in traveling acoustic waves. The artificial nanoswimmer, fabricated by multistep electrodeposition techniques, compromises a rigid bimetallic head and a flexible tail. During acoustic excitation of the nanoswimmer the tail structure oscillates, which leads to a large amplitude propulsion in traveling waves. FEM simulation results show that the structural resonances lead to high propulsive forces.
authors.affiliation: Institute of Robotics and Intelligent Systems (IRIS) and ‡Institute of Mechanical Systems (IMES), ETH Zurich , Zurich CH-8092, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ahmed
authors.forename: Thierry
authors.initials: T
authors.lastname: Baasch
authors.affiliation: Institute of Robotics and Intelligent Systems (IRIS) and ‡Institute of Mechanical Systems (IMES), ETH Zurich , Zurich CH-8092, Switzerland.
authors.forename: Bumjin
authors.initials: B
authors.lastname: Jang
authors.affiliation: Institute of Robotics and Intelligent Systems (IRIS) and ‡Institute of Mechanical Systems (IMES), ETH Zurich , Zurich CH-8092, Switzerland.
authors.forename: Salvador
authors.initials: S
authors.lastname: Pane
authors.forename: Jürg
authors.initials: J
authors.lastname: Dual
authors.affiliation: Institute of Robotics and Intelligent Systems (IRIS) and ‡Institute of Mechanical Systems (IMES), ETH Zurich , Zurich CH-8092, Switzerland.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Nelson
keywords: Acoustic; flagella; motor; nanoswimmer; propulsion; ultrasound