Controlled drop emission by wetting properties in driven liquid filaments

The controlled formation of micrometre-size drops is of importance for many technological applications such as microfluidics. A wetting-based destabilization mechanism of forced microfilaments on either hydrophilic or hydrophobic stripes leading to the periodic emission of droplets can now be used t...

Full description

Saved in:
Bibliographic Details
Published in:Nature materials 2011-05, Vol.10 (5), p.367-371
Main Authors: Ledesma-Aguilar, R., Nistal, R., Hernández-Machado, A., Pagonabarraga, I.
Format: Article
Language:English
Subjects:
639/301/1005/190
639/301/923/1030
Biomaterials
Biotechnology
Capillarity
Chemistry and Materials Science
Condensed Matter Physics
Critical velocity
Droplets
Emission
Emissions
Emissions control
Filaments
Fluid mechanics
Friction
letter
Liquids
Materials Science
Nanotechnology
Optical and Electronic Materials
Splashing
Wetting
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The controlled formation of micrometre-size drops is of importance for many technological applications such as microfluidics. A wetting-based destabilization mechanism of forced microfilaments on either hydrophilic or hydrophobic stripes leading to the periodic emission of droplets can now be used to control independently the drop size and emission period. The controlled formation of micrometre-sized drops is of great importance to many technological applications 1 , 2 , 3 , 4 , 5 . Here we present a wetting-based destabilization mechanism of forced microfilaments on either hydrophilic or hydrophobic stripes that leads to the periodic emission of droplets. The drop emission mechanism is triggered above the maximum critical forcing at which wetting, capillarity, viscous friction and gravity can balance to sustain a stable driven contact line. The corresponding critical filament velocity is predicted as a function of the static wetting angle, which can be tuned through the substrate behaviour, and shows a strong dependence on the filament size. This sensitivity explains the qualitative difference in the critical velocity between hydrophilic and hydrophobic stripes, and accounts for previous experimental results of splashing solids 6 . We demonstrate that this mechanism can be used to control independently the drop size and emission period, opening the possibility of highly monodisperse and flexible drop production techniques in open microfluidic geometries.
ISSN:1476-1122
1476-4660
DOI:10.1038/nmat2998