title: Directional Movement of Droplets in Grooves: Suspended or Immersed?
abstract: The behavior of droplets trapped in geometric structures is essential to droplet manipulation applications such as for droplet transport. Here we show that directional droplet movement can be realized by a V-shaped groove with the movement direction controlled by adjusting the surface wettability of the groove inner wall and the cross sectional angle of the groove. Experiments and analyses show that a droplet in a superhydrophobic groove translates from the immersed state to the suspended state as the cross sectional angle of the groove decreases and the suspended droplet departs from the groove bottom as the droplet volume increases. We also demonstrate that this simple grooved structure can be used to separate a water-oil mixture and generate droplets with the desired sizes. The structural effect actuated droplet movements provide a controllable droplet transport method which can be used in a wide range of droplet manipulation applications.
authors.affiliation: State Key Laboratory of Fine Chemicals, Liaoning Provincial Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Fine Chemicals, Liaoning Provincial Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Lan
authors.affiliation: State Key Laboratory of Fine Chemicals, Liaoning Provincial Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
authors.forename: Benli
authors.initials: B
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Fine Chemicals, Liaoning Provincial Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
authors.forename: Rongfu
authors.initials: R
authors.lastname: Wen
authors.affiliation: State Key Laboratory of Fine Chemicals, Liaoning Provincial Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
authors.forename: Yansong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Fine Chemicals, Liaoning Provincial Key Laboratory of Clean Utilization of Chemical Resources, Institute of Chemical Engineering, Dalian University of Technology, Dalian 116024, China.
authors.forename: Xuehu
authors.initials: X
authors.lastname: Ma