Microcapsule synthesis via RAFT photopolymerization in vegetable Oil as a green solvent
Fumi Ishizuka, Martina H. Stenzel, Per B. Zetterlund
文献索引：10.1002/pola.28958
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摘要
ABSTRACT Polymeric capsules with an aqueous core have great potential for a wide range of applications, for example food/biomedical applications. However, synthesis of such capsules often involves the use of toxic organic solvents. Herein, an organic solvent-free approach is developed for the synthesis of polymeric microcapsules with an aqueous core. The method is based on RAFT polymerization of divinyl monomer around the periphery of inverse emulsion water droplets acting as templates, with an amphiphilic macroRAFT species fulfilling the dual roles of RAFT agent and colloidal stabilizer. Vegetable oils, which are non-toxic and renewable, are used as the continuous phase of these inverse emulsions, which are prepared using membrane emulsification to control the emulsion droplet size and size distribution. Relatively monodisperse emulsions with tunable droplet size in the range of approximately 10–30 µm are prepared, followed by the RAFT polymerization step to generate polymeric microcapsules having similar size as the initial droplets. This approach will be beneficial for various applications where toxic solvents need be minimized or removed completely to avoid adverse effects. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018. Monodisperse polymeric microcapsules with a hydrophilic core were synthesized via inverse emulsion periphery RAFT polymerization in vegetable oil as a non-toxic and renewable solvent. Inverse emulsion water droplets serve as soft templates, stabilized with amphiphilic block copolymer having dual roles as colloidal stabilizer and macroRAFT agent. Vegetable oil-based inverse emulsions are prepared via membrane emulsification. This technique allows fine tuning the polymeric capsule size via the membrane pore size.