In this project funded by National Science Foundation, an experimental method was developed to measure the adhesion between a solid and a liquid. The method was tested on several systems and a comparison with theoretical understanding and literature estimates showed that this is indeed the work of adhesion, measured directly for the first time.
Soli-liquid work of adhesion is a central parameter that plays a role in many processes and products such as contact lenses, fuel cells and oil extraction from porous tocks. So far it was estimated indirectly from contact angle measurements. An instrument (Centrifugal Adhesion Balance) was constructed, which allows a physical separation of a liquid from a solid in the normal direction. This is achieved by a combination of centrifugal and gravitational forces so as to allow decoupling between normal and lateral forces. A mathematical model was developed to enable the interpretation of the measured results (which are in units of force) to work (which is in units energy). It was shown that the experiment and model provide accurate values of work of adhesion. The values agree with literature understanding.
This project was funded the National Science Foundation.