Sessile Drop Tester

Water repellency is a major problem for soils. The best method for quantifying the magnitude of repellency is by measuring the angle between the water droplet and a layer of ordinary sand.

This set-up is a conversion tool that allows sessile drop measurements with a conventional Leica macroscope. The first-order optical mirror (a standard secondary mirror for a Newtonian telescope) reflects the light path under a 90 degree angle to the sand and water droplet that are position on a small table. This table is moved up and down using a spring-tensioned cantilever. The installed ball bearings and the Mitutoyo micrometer allow a smooth continuous motion up and down.

The set up is developed for preparatory experiments for the Fly Your Thesis project that flies onboard the ESA parabolic flight campaign of 2011. More info van be found on:

http://www.science.uva.nl/ibed/news-archive.cfm/50236157-1321-B0BE-6813850E6F0980D8

http://folia.nl/archief/jaargang_63/Folia20_63.pdf (pages 16-17, in Dutch)