By Kibron Inc.
Dynamic contact angle measurements characterise how a liquid and solid interact during the course of a wetting and de-wetting process providing further information on the surface roughness and (in)homogeneity of the sample surface. Wetting properties benefit the scientific investigator in many industrial applications such as hair care science, printing, oil recovery & fibre re-inforcement for composites / aerospace. The Wilhelmy balance method uses a microbalance to measure the force exerted on a solid when it is immersed into the wetting liquid of interest. In a dynamic contact angle measurement using the Kibron EZ-Pi Plus the standard measuring probe is replaced by a sample. The force exerted by a chosen test liquid on the sample is measured as a function of immersion depth and pull direction. When the perimeter of the sample and surface tension of test liquid are known, (or measured) the dynamic contact angle can be calculated. For macroscopic samples the force must be corrected for buoyancy. The contact angle when the sample is immersed into the liquid is called the advancing contact angle (wetting) and when the sample is withdrawn it is termed the receding contact angle (de-wetting). The difference between advancing / receding contact angle is known as the hysteresis, and provides insight into surface wetting and roughness. Wetting measurements on single fibers, for textiles, hair and fiber re-inforcement applications
