Impacting-bouncing nanodroplets on superhydrophobic surfaces under electric fields
Journal
Colloids and Surfaces A: Physicochemical and Engineering Aspects
Journal Volume
629
Date Issued
2021
Author(s)
Abstract
Because electric fields can significantly modify the morphology of impacting droplets, the impact dynamics of droplets subjected to external electric fields have attracted extensive attention in recent years. Owing to the enhanced viscous effect and the altered viscous dissipation mechanisms, nanodroplets show distinctly different impact behaviors from macroscale droplets. However, it is not clear how electric fields affect the impact dynamics of nanodroplets, especially when the field direction is changed. In this study, molecular dynamics (MD) simulations were performed to reveal the bouncing dynamics of a nanodroplet impacting a hydrophobic surface under electric fields with various field strengths and directions. As compared with the case without an electric field, the bouncing dynamics of the nanodroplet were significantly modified in the presence of the electric fields with tilt angles of α = 0°, 30°, 45°, 60°, and 90°, especially when the field strength was higher than 0.08 V ??1. The restitution coefficient, εb, was enhanced by the electric fields at a non-zero α with strengths larger than 0.08 V ??1. Applying an electric field with α = 60° and ? 0.08 V ??1 would lead to the maximum bouncing velocity. The contact time was stretched by a perpendicular electric field when E ? 0.08 V ??1. When the impact velocity was not sufficient to make a droplet bounce off, an electric field with all directions was capable to cause the opposite. ? 2021 Elsevier B.V.
Subjects
Droplet bouncing
Droplet impact
Electric field direction
Electrowetting
LAMMPS
Molecular dynamics
Drops
Electric fields
Hydrophobicity
Morphology
Surface chemistry
Viscous flow
Droplets impact
Electric-field directions
Field strengths
Impact dynamics
Nano-droplets
Super-hydrophobic surfaces
article
contact time
electric field
electrowetting
hydrophobicity
molecular dynamics
SDGs
Type
journal article