Ring to Mountain Transition in Deposition Pattern of Drying
  When a droplet containing a non-volatile component is dried on a substrate, it leaves a ringlike deposit on the substrate. We propose a theory which predicts the deposit distribution based on a model of fluid flow and contact line motion of the droplet. It is shown that the deposition pattern changes continuously from coffee-ring to volcano-like and to mountain-like depending on the mobility of the contact line and the evaporation rate. Analytical expression is given for the peak position of the distribution of deposit left on the substrate. 
Xingkun Man and Masao Doi
cond-mat.soft