Chemicals Research Laboratories, Toray Industries, Inc. , 9-1, Oe-cho, Minato-ku, Nagoya 455-8502, Japan.
J Am Chem Soc. 2016 Apr 13;138(14):4714-7. doi: 10.1021/jacs.6b01697. Epub 2016 Apr 5.
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.
我们展示了一种通过在含有聚苯乙烯（PS）和聚丁二烯（PB）的油包水乳状液中混合 AC 和 BC 嵌段共聚物来制备不对称聚合物囊泡的简便方法，该乳状液中的氯仿（CHCl3）。聚合物囊泡是通过在油包水乳状液中混合聚苯乙烯-b-聚（环氧乙烷）（SO）和聚丁二烯-b-聚（环氧乙烷）（BO）来制备的，其中液滴和连续相分别富含 PS 和 PB。使用带有荧光染料标记的 SO 和 BO 通过共焦荧光显微镜直接可视化聚合物囊泡的结构；具有高 O 嵌段分数的 SO 和 BO 共同组装以产生不对称聚合物囊泡。由于 O 嵌段在 PS 和 PB 中均不溶，我们推断聚合物囊泡的详细结构是双层的，其中 S 和 B 嵌段分别朝向 PS 内层和 PB 外层，而常见的 O 嵌段形成核膜。只有当 O 嵌段足够长时，才会观察到这种结构。值得注意的是，尽管所有聚合物都可溶于 CHCl3，但这种复杂的结构是通过简单的共组装形成的。这些不对称聚合物囊泡应该为乳液液滴周围提供坚固的双层膜，从而形成两种流体的稳定纳米分散体。
