Sessile drop tests substrate requirements

The five main requirements for conduct of a sessile drop experiment relevant to high temperature capillary phenomena are characterisation of the materials, a flat horizontal substrate, a test chamber to provide a controlled and generally inert gaseous environment, a facility that heats the sample to a predetermined temperature and a means of measuring the geometry and size of the sessile drop. Satisfying these requirements demands careful and precise experimental procedures. 

Some form of mechanical pumping will be required to purge or evacuate and back fill the test chamber and care must be taken to minimise transmission of vibration to the sample. Vibration that causes movement of the sessile drop over its substrate is unacceptable and generally any vibration that can be felt by placing a hand on the test chamber should be avoided. 

---