Oil-in-Oil Emulsions Stabilized by Asymmetric Polymersomes Formed by AC + BC Block Polymer Co-Assembly

Itaru Asano, Soonyong So, Timothy P. Lodge

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


We demonstrate a facile route to asymmetric polymersomes by blending AC and BC block copolymers in oil-in-oil emulsions containing polystyrene (PS) and polybutadiene (PB) in chloroform (CHCl3). Polymersomes were prepared by mixing polystyrene-b-poly(ethylene oxide) (SO) and polybutadiene-b-poly(ethylene oxide) (BO) in the oil-in-oil emulsion, where the droplets and continuous phase are PS- and PB-rich, respectively. The polymersome structure was directly visualized using dye-labeled SO and BO with confocal fluorescence microscopy; SO and BO with a high O block fraction co-assemble to produce asymmetric polymersomes. As the O block is insoluble in both PS and PB, we infer that the detailed structure of the polymersomes is a bilayer in which the S and B blocks face the PS-inner and PB-outer phases, respectively, while the common O blocks form the core membrane. This structure is only observed for sufficiently long O blocks. It is remarkable that although all the polymers are soluble in CHCl3, such elaborate structures are created by straightforward co-assembly. These asymmetric polymersomes should provide robust bilayer membranes around emulsion droplets, leading to stable nanoscopic dispersions of two fluids.

Original languageEnglish (US)
Pages (from-to)4714-4717
Number of pages4
JournalJournal of the American Chemical Society
Issue number14
StatePublished - Apr 27 2016

Bibliographical note

Funding Information:
This research was supported by Toray Industries, Inc. and by the National Science Foundation (DMR-1206459). CFM imaging was carried out at the Imaging Center, University of Minnesota. We thank Sujay Chopade for experimental help, Prof. Marc Hillmyer for the use of SEC, and Prof. Valerie Pierre for access to a UV-vis spectrometer.

Publisher Copyright:
© 2016 American Chemical Society.


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