title: Giant-amplitude, high-work density microactuators with phase transition activated nanolayer bimorphs.
abstract: Various mechanisms are currently exploited to transduce a wide range of stimulating sources into mechanical motion. At the microscale, simultaneously high amplitude, high work output, and high speed in actuation are hindered by limitations of these actuation mechanisms. Here we demonstrate a set of microactuators fabricated by a simple microfabrication process, showing simultaneously high performance by these metrics, operated on the structural phase transition in vanadium dioxide responding to diverse stimuli of heat, electric current, and light. In both ambient and aqueous conditions, the actuators bend with exceedingly high displacement-to-length ratios up to 1 in the sub-100 μm length scale, work densities over 0.63 J/cm(3), and at frequencies up to 6 kHz. The functionalities of actuation can be further enriched with integrated designs of planar as well as three-dimensional geometries. Combining the superior performance, high durability, diversity in responsive stimuli, versatile working environments, and microscale manufacturability, these actuators offer potential applications in microelectromechanical systems, microfluidics, robotics, drug delivery, and artificial muscles.
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States.
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.forename: Chun
authors.initials: C
authors.lastname: Cheng
authors.forename: Zhenting
authors.initials: Z
authors.lastname: Cheng
authors.forename: Kevin
authors.initials: K
authors.lastname: Wang
authors.forename: Ramamoorthy
authors.initials: R
authors.lastname: Ramesh
authors.forename: Junqiao
authors.initials: J
authors.lastname: Wu
mesh_terms: D004560:Electricity; D004867:Equipment Design; D006358:Hot Temperature; D008027:Light; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D055616:Microtechnology; D010087:Oxides / Q000737:chemistry*; D044367:Phase Transition; D014159:Transducers; D017968:Vanadium Compounds / Q000737:chemistry*
chemical_list: D010087:Oxides; D017968:Vanadium Compounds; C581824:vanadium dioxide