Figure 4
Visualisation of the formation of the solid surface structure and the sol-gel transition from a single drop formed by inkjet printer on the glass surface.
(a)a model of the drop solidification upon drying accompanied by the formation of a pie-drop structure (b), which can be measured by atomic force microscopy (c) and scanning electron microscopy to determine the nanoscale structure of the drop. AFM roughness measurements evidence the coffee-ring effect evident from a substantial difference in the height of the edge and the inner parts of the drop with respect to the substrate. False color SEM (e) and HRSEM (f) images of the drop on the glass substrate further confirm the coffee-ring effect on the drop.
