This book deals with an important phenomenon popularly known as wetting. In the process of wetting three phases meet along a line, and surfactants have enormous impact on wetting and spreading. The book is organized into five chapters.
Chapter 1 deals with Young’s equation which forms the backbone of the subject. It prepares the reader to appreciate the equilibrium and kinetics of wetting. A detailed explanation of surface forces and disjoining pressure has been incorporated. Static hysteresis of contact angle, which is important from practical point of view, also finds a mention.
Chapter 2 discusses equilibrium wetting phenomena, in particular equilibria of various films. The films on heterogeneous nonplanar and rough surfaces are analysed. The authors also explain here the significant difference between the equilibria of drop and meniscus: the drop size adjusts in equilibrium to the imposed pressure, whereas in the case of equilibrium of meniscus in a capillary the vapour pressure alone allows the equilibrium.
Starting with the Navier-Stokes equations, chapter 3 develops the kinetics of wetting on solid surfaces and in capillaries. Analytical treatments as well as experimental details make the subject matter clear. The cases of complete and partial wetting are identified and explained.
In chapter 4, the authors describe how the printing, paint, health and home-care product industries use the phenomena of spreading over porous substrates. The study reveals that in the case of complete wetting, the hysteresis of contact angle is present and depends on the flow in the porous substrate.
Chapter 5 is devoted to the spreading of aqueous surfactant solutions over porous layers and non-porous substrates. The comparison of experimental results with theoretical predictions shows reasonable agreement. The authors give an analytical treatment of Marangoni flow and explain its impact on the superspreading. The reader can also find here an interesting discussion on spreading of drops of non-Newtonian fluids.
In conclusion, the authors have given a very coherent presentation of the subject matter, which will be appreciated by researchers as well as new entrants in this expanding area of research.