10.1021/acs.langmuir.5b04630.s001 Ziyang Lu Ziyang Lu Shuhua Peng Shuhua Peng Xuehua Zhang Xuehua Zhang Influence of Solution Composition on the Formation of Surface Nanodroplets by Solvent Exchange American Chemical Society 2016 phase diagram droplet size unit surface area droplets bulk droplet formation Solvent ExchangeSolvent exchange substrate 2016-01-27 00:00:00 Media https://acs.figshare.com/articles/media/Influence_of_Solution_Composition_on_the_Formation_of_Surface_Nanodroplets_by_Solvent_Exchange/2074234 Solvent exchange is a simple process of forming surface nanodroplets on an immersed substrate. In this process, the droplets nucleate and grow in response to transient oversaturation when a good solvent of the droplet liquid is displaced by a poor solvent. Here we will show how the final droplet size is influenced by solution composition in the solvent exchange. To do this, we produced water droplets on a hydrophilic substrate and cyclohexane droplets on a hydrophobic substrate by using a tertiary system of cyclohexane, ethanol, and water. The composition of the good solvent was varied systematically in the one-phase region on the phase diagram. We found that the key feature closely related to the droplet size is the area (<i>A</i>) in the phase diagram defined by the phase boundary and the concentration ratio between the good solvent and the droplet liquid. This area reflects the excessive amount of droplet liquid in the tertiary mixture, which can be complicated by bulk droplet formation during solvent exchange. We will also show that the droplet volume per unit surface area also increases with <i>A</i>. The findings from this work will provide guideline for the selection of solution conditions to achieve a desirable droplet size and number density on the surface.