In vitro wettability is measured by different techniques: the sessile drop method
, captive bubble or Whilhelmy Plate.
The contact angle measurements used to evaluate the surface wettability of PPT were performed by the sessile drop method
were carried out using Kruss Easy Drop system (DSA20).
The contact angle was measured by the Sessile drop method
, where the angle is measured between the base line (the line of touch of the surface) and the tangent on the drop curve in the point where solid, liquid and air phase meat.
1993) determined that the sessile drop method gave the lowest contact angles and was the least reproducible when compared to the Wilhelmy balance and tilted plate methods.
Gaclawski & Urbaniak-Domagala (2007) emphasize the significance of capturing the reflection point clearly for the sessile drop method.
Newmann Triangle: The Neumann triangle or sessile drop method is very similar to the pendant drop method, consisting of the study of the profile of a drop of one liquid resting on a flat plate surrounded by another liquid of smaller density (in the case of the determination of interfacial tension) or by air (in the case of determination of surface tension) at mechanical equilibrium.
A new variation of the sessile drop method consists of using the Neumann triangle (12, 13), to evaluate the interfacial tension between two liquids.
The advantages of using pendant and sessile drop methods
are as follows.