Trapping of Water Drops by Defects on Superhydrophobic Surfaces
(English)Manuscript (preprint) (Other academic)
In this work the effect of line‑shaped defects on the motion of water drops on superhydrophobic surfaces have been investigated using high‑speed video. The defects were introduced on superhydrophobic wax surfaces by a simple scratching method. It is shown that the motion of the drop in the vicinity of the defect can be approximated by a damped harmonic oscillator. Whether a drop gets trapped or not while traversing the defect is determined by the incident speed and the characteristics of the oscillator, more specifically by the damping ratio z and the nondimensional forcing constant â. We also show that it is possible to predict the trapping speed as well as the exit speed using a simple work‑energy consideration in systems with negligible viscous dissipation.
Research subject Chemical Engineering
IdentifiersURN: urn:nbn:se:kth:diva-156400OAI: oai:DiVA.org:kth-156400DiVA: diva2:766502
QS 20142014-11-272014-11-272015-05-01Bibliographically approved