Measuring Surface Tensions of Soft Solids with Huge Contact-Angle Hysteresis

The equilibrium contact angle of a droplet resting on solid substrate can reveal essential properties the solid's surface. However, when motion surface shows significant hysteresis, it is generally accepted that cannot be determined. Here, we describe method to measure tensions soft solids with strong wetting hysteresis. With independent knowledge tension fluid and linear-elastic response solid, deformations under line single together difference in against liquid vapor phases. If elastic are unknown, then this determined from change angle. These results an alternate angle, equivalent classic form Young-Dupr\'{e}, but place energies. We motivate apply approach experiments gelatin, common hydrogel.