title: Propulsion Mechanism of Catalytic Microjet Engines.
abstract: We describe the propulsion mechanism of the catalytic microjet engines that are fabricated using rolled-up nanotech. Microjets have recently shown numerous potential applications in nanorobotics but currently there is a lack of an accurate theoretical model that describes the origin of the motion as well as the mechanism of self-propulsion. The geometric asymmetry of a tubular microjet leads to the development of a capillary force, which tends to propel a bubble toward the larger opening of the tube. Because of this motion in an asymmetric tube, there emerges a momentum transfer to the fluid. In order to compensate this momentum transfer, a jet force acting on the tube occurs. This force, which is counterbalanced by the linear drag force, enables tube velocities of the order of 100μm/s. This mechanism provides a fundamental explanation for the development of driving forces that are acting on bubbles in tubular microjets.
authors.affiliation: Institute for Integrative Nanosciences, Leibniz Institute for Solid State and Materials Research Dresden, Dresden 01069, Germany ( v.fomin@ifw-dresden.de ).
authors.forename: Vladimir M
authors.initials: VM
authors.lastname: Fomin
authors.affiliation: Institute for Integrative Nanosciences, Leibniz Institute for Solid State and Materials Research Dresden, Dresden 01069, Germany; Dresden University of Technology, Dresden 01069, Germany ( hippler.m@gmail.com ).
authors.forename: Markus
authors.initials: M
authors.lastname: Hippler
authors.affiliation: Institute for Integrative Nanosciences, Leibniz Institute for Solid State and Materials Research Dresden, Dresden 01069, Germany ( v.magdanz@ifw-dresden.de ).
authors.forename: Veronika
authors.initials: V
authors.lastname: Magdanz
authors.affiliation: Institute for Integrative Nanosciences, Leibniz Institute for Solid State and Materials Research Dresden, Dresden 01069, Germany; Max Planck Institute for Intelligent Systems, Stuttgart 70569, Germany ( soler@is.mpg.de ).
authors.forename: Lluís
authors.initials: L
authors.lastname: Soler
authors.affiliation: Institute for Integrative Nanosciences, Leibniz Institute for Solid State and Materials Research Dresden, Dresden 01069, Germany; Max Planck Institute for Intelligent Systems, Stuttgart 70569, Germany ( sanchez@is.mpg.de ).
authors.forename: Samuel
authors.initials: S
authors.lastname: Sanchez
authors.affiliation: Institute for Integrative Nanosciences, Leibniz Institute for Solid State and Materials Research Dresden, Dresden 01069, Germany; Material Systems for Nanoelectronics, Chemnitz University of Technology, Chemnitz 09126, Germany; Center for Advancing Electronics Dresden, Dresden University of Technology, Dresden 01187, Germany ( o.schmidt@ifw-dresden.de ).
authors.forename: Oliver G
authors.initials: OG
authors.lastname: Schmidt
keywords: Catalytic microjets; micromotors; modeling; physics; propulsion; self-assembled microtubes; system performance