Header menu link for other important links
X
Self-driven droplet transport: Effect of wettability gradient and confinement
Imdad Uddin Chowdhury, ,
Published in American Institute of Physics Inc.
2019
Volume: 31
   
Issue: 4
Abstract
Surface tension driven droplet transport in an open surface is increasingly becoming popular for various microfluidic applications. In this work, efficient transport of a glycerin droplet on an open wettability gradient surface with controlled wettability and confinement is numerically investigated. Nondimensional track width w∗ (ratio of the width of the wettability gradient track w and the initial droplet diameter d0) of a wettability gradient track laid on a superhydrophobic background represents wettability confinement. A lower value of w∗ represents higher wettability confinement. Droplet behavior changes for different wettability confinements and gradients of the track. It is found that droplet velocity is a function of the wettability confinement and the gradient; droplet transport velocity is maximum for w∗ = 0.8. Higher confinement (w∗ < 0.8) leads to a significant reduction in droplet velocity. Droplet transport characteristics on hydrophilic-superhydrophilic, hydrophobic-superhydrophilic, and superhydrophobic-superhydrophilic tracks are studied. It is found that for a fixed length of the track, droplet velocity is maximum for the superhydrophobic-superhydrophilic track. A droplet transport regime is demonstrated for a wettability gradient track with different confinements, and it is found that the droplet is transported for wettability confinement w∗ > 0.6 irrespective of the wettability gradient of the track. These findings provide valuable insight into efficient droplet manipulation in microfluidic devices. © 2019 Author(s).
About the journal
JournalData powered by TypesetPhysics of Fluids
PublisherData powered by TypesetAmerican Institute of Physics Inc.
ISSN10706631
Open AccessNo
Concepts (14)
  •  related image
    Hydrophilicity
  •  related image
    Hydrophobicity
  •  related image
    Microfluidics
  •  related image
    Velocity
  •  related image
    Wetting
  •  related image
    DROPLET BEHAVIORS
  •  related image
    Droplet diameters
  •  related image
    DROPLET MANIPULATION
  •  related image
    DROPLET TRANSPORT
  •  related image
    MICRO FLUIDIC APPLICATIONS
  •  related image
    Micro-fluidic devices
  •  related image
    SUPER-HYDROPHILIC
  •  related image
    WETTABILITY GRADIENTS
  •  related image
    Drops