Dynamics of Wetting

The wetting dynamics form the foundation to analyze various problems including solid-liquid interfacial behavior, such as dynamics of bubble, droplet or liquid film on a wall. This book introduces some essential concepts of wetting and offers comprehensive treatments to analyze modern engineering topics observed in various industrial fields. In the part of fundamental principle, some basic ideas of interfacial tensions and contact angles are explained mainly from a dynamic viewpoint. The book also introduces some new methods to measure surface tension as well as for advancing and receding contact angles, and briefly touches on the basic principle of controling the wettability of a solid plates. either a or s, not both! In the part of application, some real-world problems related to wetting phenomena are discussed in detail. Based on the physical mechanism of contact angle hysteresis, sliding of droplets on inclined plates or on a vertical cylinder and detachment of pendant droplet from a curved surface are analyzed from a thermodynamic viewpoint based on the energy minimum principle. In recent progressing industrial techniques such as lab-on-a-tip or microfluidics, it is important to understand the dynamic wetting phenomenon in which contact angles are dependent on the velocity of three-phase contact line. The authors present a wide variety of experimental and MD results for dynamic contact angles appeared in capillary tubes or two-dimensional meniscus on a moving plate. The dynamics of wetting is discussed from theoretical and numerical results with the concept of Navier's slip condition on the wall. The book also introduces some important applicative topics in handling ink jet devices or surfactant solutions, such as a CFD model to appropriately express the force balance on the contact line, the effect of surface viscosity or dynamic surface tension on the stability of surfactant liquid sheet or droplet, and some unique wetting phenomena observed in steel manufacturing process.