Dynamical model for chemically driven running droplets.
We propose coupled evolution equations for the thickness of a liquid film and the density of an adsorbate layer on a partially wetting solid substrate. Therein, running droplets are studied assuming a chemical reaction underneath the droplets that induces a wettability gradient on the substrate and provides the driving force for droplet motion. Two different regimes for moving droplets--reaction-limited and saturated regime--are described. They correspond to increasing and decreasing velocities with increasing reaction rates and droplet sizes, respectively. The existence of the two regimes offers a natural explanation of prior experimental observations.
Thiele
Uwe
U
Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Strasse 38, D-01187 Dresden, Germany. thiele@mpipks-dresden.mpg.de
John
Karin
K
Bär
Markus
M
D004058:Diffusion; D008055:Lipids / Q000737:chemistry*; D008962:Models, Theoretical; D010825:Physics / Q000379:methods*; D012997:Solvents
D008055:Lipids; D012997:Solvents