ABSTRACT
A. Basics of Wetting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 1. Wetting and Wettability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 2. Three Phase Contact (TPC) Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 3. Contact Angle Hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
B. Wetting on Rough Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 1. Surface Roughness of Solids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 2. Different Wetting Regimes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
C. Wetting Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 1. Spreading Theories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 2. Spreading as a Rate Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 3. Spreading of Aqueous Surfactant Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 4. Spreading in Technological Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
D. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 E. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 F. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
A. Basics of Wetting
The physical bases of wetting are molecular interactions within a solid or liquid or across the interface between a liquid and a solid. The wetting behavior of liquids on solid surfaces is determined by surface tensions (strictly speaking by interfacial tensions) of solid or liquid and liquid-solid interfacial tensions. Curvature and roughness of contact surface are the two other critical factors for wetting phenomena.
