We demonstrate a scalable continuous feed method for the synthesis of polymer Janus nanoparticles with different composition and with different aspect ratios between lobes, including with one hard cross-linked polystyrene lobe and one soft film-forming poly(methyl methacrylate-co-butyl acrylate) (P(MMA-co-BA)) lobe, through reversible addition–fragmentation chain transfer (RAFT)-mediated emulsion polymerization. Snowman shaped particles of size around 40 nm are synthesized through a continuous monomer feeding method, which enables kilogram-scale synthesis of diverse polymer Janus nanoparticles, with a solids content greater than 30%. The Janus nanoparticles with the soft P(MMA-co-BA) lobes spontaneously self-assemble around solid particles in an aqueous phase, forming a thin (5–100 nm) polymer film that completely encapsulates the solid particles. The process is achieved at room temperature and under mild conditions. The film-forming Janus nanoparticles show excellent encapsulation ability for a variety of solid particles, such as organic and inorganic pigments, carbon nanotubes and calcite, without requiring polymerization to be conducted in the presence of the solid particles. When the Janus nanoparticles were used to encapsulate calcite particles in low sheen paints, the encapsulation provided superior stain resistance to the formed paint film.

中文翻译：

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软硬Janus纳米颗粒，用于固体颗粒的聚合物封装

我们证明了聚合物纳米颗粒的Janus具有不同组成并与凸角之间不同的纵横比，其中包括与一个硬交联聚苯乙烯瓣和一个软成膜聚合成一个可伸缩的连续进料方法（甲基丙烯酸甲酯-共-丙烯酸丁酯） （P（MMA- co -BA ））叶，通过可逆加成-断裂链转移（RAFT）介导的乳液聚合。通过连续单体进料方法合成了大小约为40 nm的雪人状颗粒，该方法能够以千克规模合成各种聚合物Janus纳米颗粒，固体含量大于30％。具有柔软P（MMA- co-BA）叶片在水相中自发地围绕固体颗粒自组装，形成薄的（5–100 nm）聚合物膜，该膜完全包裹了固体颗粒。该过程在室温和温和条件下完成。成膜的Janus纳米颗粒显示出对各种固体颗粒（如有机和无机颜料，碳纳米管和方解石）的出色封装能力，而无需在固体颗粒存在下进行聚合。当Janus纳米颗粒用于将方解石颗粒包裹在低光泽油漆中时，该包裹对形成的漆膜具有出色的耐污染性。