The ability to control the deposition of the coacervates formed during evaporation on the substrate was investigated. As previously explained, when allowed to evaporate at room temperature, the capillary forces distribute the coacervates to the perimeter of the droplet, where they coalesce, forming larger and larger particles the closer they get to the edge (Figure and Video S3). By placing the evaporating droplet underneath an external source of ethanol vapors, the Marangoni effect could be enhanced, opposing the capillary flow and flipping the size gradient (Figure ). The larger coacervates that appeared underneath the vapor source indicate that the Marangoni flow transported the coacervates to this area where they coalesced, forming larger coacervates inside the droplet. When deposited on a hydrophobic substrate, the Marangoni flow transported the coacervates to the center of the droplet (Figure ). The coalescence that results in larger coacervates is not distinct on the hydrophobic substrate, probably due to the longer duration of evaporation that allowed the coacervates to solidify before congregating. The size that the coacervates can reach appeared to be directly affected by the volume of the deposited solution. A droplet of 0.2 µL gave rise to coacervates smaller than 500 nm, while 5 µL provided large coacervates with diameters of several microns (Figure ). Larger deposited volumes also resulted in more hemisphere structures. This size gradient could be eliminated when the droplets are given time to reach equilibrium before complete evaporation of the solution. This was demonstrated when the evaporating droplet was placed at 4 °C or on a hydrophobic substrate (Figure ). In these cases, no size gradient was formed, and the size distribution was more homogenous.