  Surface coatings and patterning technologies are essential for various
physicochemical applications. In this Letter, we describe key parameters to
achieve uniform particle coatings from binary solutions: First, multiple
sequential Marangoni flows, set by solute and surfactant simultaneously,
prevent non-uniform particle distributions and continuously mix suspended
materials during droplet evaporation. Second, we show the importance of
particle-surface interactions that can be established by surface-adsorbed
macromolecules. To achieve a uniform deposit in a binary mixture, a small
concentration of surfactant and surface-adsorbed polymer (0.05 wt% each) is
sufficient, which offers a new physicochemical avenue for control of coatings.
