Study of Contact Angle Hysteresis : In Relation to Boiling Surface Wettability

Abstract

The Wettability of a heated surface plays an important role in nucleate and transition boiling. In most previous research on boiling, the contact angle has been a common measure of surface wettability. However, because of hysteresis, measuring it from the shape of a liquid droplet on a solid surface has little meaning. In this research, the hysteresis of contact angle is studied theoretically, and effects of surface roughness, energetics and temperature on wettability are investigated experimentally by measuring contact angles of water on copper, aluminum, glass and Teflon surfaces under various conditions. As a result, a new method for evaluating surface wettability is proposed.