Cyclic Epipedography─Monitoring Contact Angle Changes in Dipping a Microsphere into a Liquid and Lifting from It.

We propose cyclic epipedography to monitor the wetting characteristics of a microsphere on a stem with a liquid by tracking the level of a liquid line on the sphere when the sphere is dipped into and lifted from the liquid, and therefore the level of the liquid plane at infinity changes with respect to the sphere. Analysis of still images of a video taken with a horizontally held microscope determines the two levels. The sphere allows viewing of the liquid line without being obscured by the meniscus the liquid forms with its container's wall.