Research Of The Meniscus Deformation Caused By Liquid Surface Tension Based On Scanning White-light Interferometer

Measurement of liquid surface tension is usually done by Du Noy ring or Wihelmy plate in a contactive way. Our recent work found that this can be measured in a noncontactive way through monitoring the meniscus deformation by a scanning white-light interferometer. Solution with different surface tension could generate a different meniscus in a certain beaker. The meniscus can be well described by the Young-Laplace equation. When one drop of oil, such as n-tetradecane (about 10μl), was added on the solution surface, different surface tension could generate a different function during the oil spreading on the surface. This spreading not only generates an interface of oil with solution but also deforms the original surface meniscus. We chose a specific point, such as the center point of the meniscus, as an indicator of its deformation and monitored by a scanning white-light interferometer in a noncontactive way. Our results demonstrated that this meniscus deformation can be a good measure of surface tension. As an application, we employed different glucose concentrations (3.33～12.49mmol/L) to generate different solution surface tension and the deformation caused by the spreading of n-tetradecane was well related to both the surface tension and the glucose concentration.