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Generation of High‐Order All‐Aqueous Emulsion Drops by Osmosis‐Driven Phase Separation
Author(s) -
Chao Youchuang,
Mak Sze Yi,
Rahman Shakurur,
Zhu Shipei,
Shum Ho Cheung
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201802107
Subject(s) - emulsion , aqueous solution , ternary operation , chemical engineering , materials science , aqueous two phase system , microfluidics , phase (matter) , separation process , forward osmosis , microemulsion , chromatography , membrane , nanotechnology , chemistry , pulmonary surfactant , reverse osmosis , organic chemistry , computer science , biochemistry , engineering , programming language
Droplets containing ternary mixtures can spontaneously phase‐separate into high‐order structures upon a change in composition, which provides an alternative strategy to form multiphase droplets. However, existing strategies always involve nonaqueous solvents that limit the potential applications of the resulting multiple droplets, such as encapsulation of biomolecules. Here, a robust approach to achieve high‐order emulsion drops with an all‐aqueous nature from two aqueous phases by osmosis‐induced phase separation on a microfluidic platform is presented. This technique is enabled by the existence of an interface of the two aqueous phases and phase separation caused by an osmolality difference between the two phases. The complexity of emulsion drops induced by phase separation could be controlled by varying the initial concentration of solutes and is systematically illustrated in a state diagram. In particular, this technique is utilized to successfully achieve high‐order all‐aqueous droplets in a different aqueous two‐phase system. The proposed method is simple since it only requires two initial aqueous solutions for generating multilayered, organic‐solvent‐free all‐aqueous emulsion drops, and thus these multiphase emulsion drops can be further tailored to serve as highly biocompatible material templates.