ABSTRACT
Surface tension is perhaps the most important parameter that describes the interfacial properties of a liquid, and its measurement has been the subject of a great many studies. An important subset of these techniques includes methods that rely on measuring the vertical force on a plate, rod, or ring as the surface tension “pulls” the object downward toward the liquid. Currently, the most common method to measure interfacial tension using these pull techniques has the suspended object directly attached by means of a wire to a suspended microbalance so that the force exerted can be measured as the solid is moved in precise increments. Without question this experimental arrangement can give accurate and precise results; however, two substantial problems exist. First, the attachment between the solid object and the balance must not be rigid for accurate measurement of the force. This lack of rigidity has meant that excessive weight cannot be tolerated, and hence very fragile thin rings or plates are typically used. Further, nonzero contact angles will lead to substantial errors in the ring case, and in the Wilhelmy plate case a zero contact angle is preferred to reduce draining times, which can be quite long.
