サテライト液滴の表面張力振動を利用した牛乳の粘度・表面張力同時測定

抄録

A micro-meter-sized droplet called a satellite droplet can be generated when the capillary bridge is broken. This method of generating the satellite droplet is called the capillary bridge breakup method. The droplet oscillates using surface tension as a restoring force and eventually becomes spherical. The frequency and decay time of the oscillation can be related to the surface tension and viscosity of the test liquid, respectively. Using this relation, we have developed a method to obtain viscosity and surface tension values from the surface tension oscillations of the satellite droplet. The previous measurement results for Newtonian fluids such as water and linear hydrocarbons are in good agreement with literature values. In this study, the applicability of this method to milk, a colloidal solution that might exhibits non-Newtonian properties, was examined. As a result, several behaviors not seen in Newtonian fluids were observed, such as the formation of extremely small droplets and multiple droplets. Furthermore, simultaneous measurement of viscosity and surface tension was possible for several dilutions of milk.