Determination of solid-liquid adhesion work on flat surfaces in a direct and absolute manner.

There is a long-standing need for a direct determination of solid-liquid work of adhesion due to its central role in several scientific and industrial fields. Here, a method is introduced to determine the value of adhesion work on flat surfaces directly, without the need of any model assumptions, and independently from uncertainties of contact angles. The presented method enables to determine the adhesion work separately both for advancing and receding situations. The directly measured adhesion work values were benchmarked successfully against the prediction of the Young-Dupré equation in the 0°-120° contact angle range. That is, the Young-Dupré equation was experimentally proven to be valid separately for both advancing and receding cases. The method provides an absolute, thermodynamic quantity, hence it is insensitive to the measurement parameters, moreover the resulting values can be used directly in further calculations.