The evaporation of sessile or pendant drops in still air

Abstract In the evaporation of drops on surfaces two modes of evaporation are distinguished: that at constant contact angle and that at constant contact area. A theoretical analysis of each mode is developed from which predictions can be made of evaporation rate and residual mass at any time in the life of the drop for contact angles ranging from near zero up to 180°. These predictions have been compared with known theoretical values and with experimental measurements, and it is considered that the theory is reasonably accurate for drops of mass between 1 pg and an upper limit somewhat greater than 40 mg.