Glossary

Sessile Drop Technique

This method is based on the determination of the shape of a drop sitting on the solid under study. In order to measure the receding and advancing contact angles, again the liquid has to move over the solid surface. This is arranged in different instruments either via a capillary from underneath or from the top, as schematically shown in Fig. V.6.
Scientific Setup

Figure 1: Sessile drop with growing volume; liquid delivered via a thin capillary from top or bottom, respectively 

This method is possibly superior to the plate technique, however, it requires an expensive instrumentation, including video and computer technique, and accurate mechanical parts. The advantage is the small amount of liquid and the applicability to quite a large number of systems, such as molten polymers or alloys. Commercial instruments are available from different producers, including pressure and temperature cells.
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