Time-resolved, three-dimensional quantitative microscopy of a droplet spreading on solid substrates.
A polarized microscope was used to study the spreading of mercury droplets on thin silver films. Using the differential interference contrast (DIC) method and semi-quantitative measurements of the optical path difference (OPD), the three-dimensional shape of the liquid droplet that wets the solid surface was constructed with an angle resolution of 1 degrees. The evolution of the droplet shape was determined with a time resolution of 0.04 s. The quantitative results are compared with other wetting-reaction systems. In particular, it is demonstrated that the droplet has a spherical-cup shape during the entire wetting-reaction process.
Be'er
A
A
Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel. beera@mail.biu.ac.il
Lereah
Y
Y