ABSTRACT
Wetting is important in many industrial processes, such as cleaning, drying, painting, coatings, adhesion, heat transfer, and pesticide application. The most common method of evaluating wetting is contact angle measurements. Figure 1 shows the case of a sessile drop measurement, where a small liquid drop is deposited on a solid surface. As contact is made, molecular interactions between the liquid and solid pull at the drop, advancing the contact line. When forces at the contact line reach equilibrium, the drop exhibits an advancing contact angle, Ga. The stronger the interaction, the greater the wetting. If 0a is substantially greater than zero, then the liquid is referred to as partial wetting. On the other hand, a zero or near-zero value is considered to be complete wetting.
