AN APPARATUS FOR THE CHARACTERIZATION OF THE STATIC AND DYNAMIC WETTABILITY OF COMPLEX INTERFACES

The apparatus described in this work is a novel tool which improves th e capabilities of studying the static and dynamic features of wetting. It is composed, on the one hand, of an operational part which include s the mechanical setup for the precise deposition of drops and their c orrect viewing once they start evolving on a substrate. On the other h and, a specific vision system completes the instrument and is made up of different cameras and focusing optics, capable of acquiring images at variable rates (up to 200 Hz) and of a data-processing card designe d to provide parameters such as contact angles, interfacial tensions, and spreading kinetics. Numerous examples of the use of this apparatus are provided in order to illustrate its merits within a wide range of static and dynamic situations related to the basic properties of inte rfaces. (C) 1997 American Institute of Physics.