title: Elasticity-driven droplet movement on a microbeam with gradient stiffness: a biomimetic self-propelling mechanism.
abstract: Directional movement of liquid droplets is of significance not only for certain physiological processes in nature but also for design of some microfluidic devices. In this study, we report a novel way to drive directional movement of liquid droplets on a microbeam with a varying or gradient stiffness. We use the energy method to theoretically analyze the interaction between a droplet and the elastic microbeam. The system tends to have the minimum potential energy when the droplet moves to the softer end of the beam. Therefore, a gradient change of the bending stiffness may be utilized to help the directional motion of droplets. Similarly, one can also drive droplets to move in a designed direction by varying the cross sectional geometry of the beam. Finally, some possible applications of this self-propelling mechanism are suggested.
authors.affiliation: FML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.
authors.forename: Xiu-Peng
authors.initials: XP
authors.lastname: Zheng
authors.forename: Hong-Ping
authors.initials: HP
authors.lastname: Zhao
authors.forename: Ling-Tian
authors.initials: LT
authors.lastname: Gao
authors.forename: Jian-Lin
authors.initials: JL
authors.lastname: Liu
authors.forename: Shou-Wen
authors.initials: SW
authors.lastname: Yu
authors.forename: Xi-Qiao
authors.initials: XQ
authors.lastname: Feng
mesh_terms: D032701:Biomimetics; D002621:Chemistry / Q000379:methods; D004548:Elasticity; D004867:Equipment Design; D004864:Equipment and Supplies; D008422:Materials Testing; D044085:Microfluidics; D015233:Models, Statistical; D008962:Models, Theoretical; D009038:Motion; D009068:Movement; D011312:Pressure; D013499:Surface Properties