Shaping droplet by semiflexible micro crystallizer for high quality crystal harvest.

Inspired by 'Hufu' in ancient China, we manufactured semiflexible micro crystallizer with two aspectant sessile platforms by 3D-printing technique that can construct a series of heteromorphic droplets (HDs) via stretching droplet height. By coordinating the gas–liquid interface and flow intensity (i.e., Ra/Ma), central-converging micro-flows were generated, which dominated solute and particle motion towards droplet center. Efficient harvest of single cubic NaCl crystal was achieved at platform center under wide volume and concentration ranges. [Display omitted] Droplet crystallization behavior held great potential in crystal preparation, micromaterial engineering, and molecular assembly. However, restricted by natural surface tension, the intrinsic crystallization regulation and efficient harvest of high quality crystal in diverse droplet features were still a great challenge. Herein, we developed a 3D printed semiflexible micro crystallizer with two aspectant sessile platforms that could simultaneously construct a series of heteromorphic droplets (HDs) and controllable HD shape. By shaping HD on the interface of the platform, central-converging micro-flows were generated by coordinating the gas–liquid interface and flow intensity (i.e., Ra/Ma) during HD crystallization from 'barrel', 'can', to 'sand clock' shape, which was validated via simulative and experimental research. Therefore, HDs, constructed in semiflexible micro crystallizer, exhibited efficient screening (>70 %) of single cubic crystal just at the center zone of platform, even under wide ranges of concentration and volume, manifesting excellent repeatability on high quality crystal harvest and relevant interfacial science research. [ABSTRACT FROM AUTHOR]