Figure 1. The suppressed coffee ring effect with increasing evaporation rate.

(a,b) Images and morphology profiles of the final deposition by drying at room temperature (a, T = 25 °C) and high temperature (b, T = 75 °C) with constant humidity (50%). Most of the particles deposit at drop edge forming ring-like fashion when drying at slow evaporation rate. In contrast, a uniform deposition is formed with only a tiny part of the particle deposited on edge when drying at high temperature. (c) The cross section area proportion (S/S_total) of ring region decreases as that of the center region arises when the evaporation temperature rises, indicating the gradually suppression of coffee-ring effect. (d) Highly ordered assembling of the monodispersed particles. The scale bar, 0.5 mm in (a,b), 1 μm in (d).