Interfacial confined droplet on sessile platform for crystal screening and harvest

Abstract The crystallization process in small droplet possessed wide engineering applications in micromaterial fabrication and fine crystal screening. Herein, hydrophilic sessile platform via 3D printing technology was developed to facilely construct the interfacial confined droplets (ICDs) with a designed contact angle by conveniently regulating the droplet volume. The micro‐flows inside the droplet were adjusted by controlling the intensity of Marangoni flow and capillary flow within different droplet shapes (i.e., contact angle), which were verified by experimental and simulative results. Especially for the 120° ICD, the micro‐flows, achieved by the coordination of Marangoni flow and capillary flow, could convey solutes toward droplet center and harvest a standard cubic crystal at sessile platform center. These results indicated that ICD and sessile platform possessed great potential on high‐quality crystal screening and crystallization technique development, which additionally enriched the research strategy on crystal engineering.