Formation of aqueous-core polymer capsules exhibiting an upper critical solution temperature (UCST) was achieved using surfactant–polymer interfacial complexation in water-in-oil inverse emulsions. In fluorinated oil, Coulombic interactions between Krytox, an anionic oil-soluble surfactant, and a cationic poly(lysine) grafted with poly(acrylamide-co-acrylonitrile) enabled the formation of an adsorbed polymer shell at the surface of water droplets. The thermoresponsiveness of the polymer shell was assessed by fluorescence microscopy with and without the presence of nanoparticles, including gold particles. We show that, above the cloud point, polymers with a balanced fraction of UCST grafts form flat adlayers that (i) spontaneously entrap nanoparticles upon cooling and (ii) switch from fluid-like dynamics at high temperature to solid-like dynamics below the cloud point. This system offers a straightforward mean to prepare temperature-sensitive capsules in mild, biocompatible conditions and to concentrate nanoparticles (including nanoheaters) in their shell.

中文翻译：

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界面络合形成的UCST型聚合物胶囊

使用油包水反相乳液中的表面活性剂-聚合物界面络合，可以形成具有上限临界溶解温度 (UCST) 的水芯聚合物胶囊。在氟化油中，Krytox（一种阴离子油溶性表面活性剂）与接枝有聚（丙烯酰胺）共聚物的阳离子聚（赖氨酸）之间的库仑相互作用-丙烯腈）能够在水滴表面形成吸附的聚合物壳。聚合物壳的热响应性通过荧光显微镜评估，无论是否存在纳米颗粒，包括金颗粒。我们表明，在浊点以上，具有平衡部分 UCST 接枝的聚合物形成平坦的adlayer，（i）在冷却时自发捕获纳米颗粒，（ii）从高温下的流体状动力学转变为云下的固体状动力学观点。该系统提供了一种直接的方法，可以在温和、生物相容的条件下制备温度敏感胶囊，并将纳米颗粒（包括纳米加热器）浓缩在它们的外壳中。