ABSTRACT
In this chapter the main interfaces involving pristine (pure and ion-free) condensed water (liquid and solid) are explored. Among the many interfaces that liquid water can build, two of them are of particular interest. One is the extremely important water vapor/liquid water interface. Needless to say how important it is inasmuch as it accounts for more than 70% of the Earth’s surface and we experience this interface every single day of our lives. The other interesting interface involves organic molecules. In the case of amphiphilic molecules (with both hydrophilic and hydrophobic groups), water is able to organize such molecules in a well-defined structure, acting as a structuring media. Such ability enables the formation of micelles and biomembranes, so it is easily understandable how important they are for cellular life. On the other hand, they are the basis of cleaning agents such as detergents. We also show that liquid water can be undercooled (remain liquid below 0◦C) on solid water (ice), and the presence of such a layer has important consequences for the low friction of ice as well as for the depletion of the ozone layer. We also discuss the amazing tendency of the surface of ice to become ordered at very low temperatures, overcoming proton disorder.
