Theta Pulsating Drop

An optical tensiometer records drop images and analyzes the drop shape automatically. The drop shape is a function of the surface tension of the liquid, gravity and the density. On a solid, the drop shape and the contact angle also depends on the properties of the solid (e.g. surface free energy, topography). The captured image is analyzed with a drop profile fitting method in order to determine contact angle and surface tension. Surface free energy can be calculated by performing contact angle measurements with several known liquids.