Three-dimensional (3D) superlattice materials self-assembled from functional inorganic nanoparticles (NPs) have attracted extensive attention due to the unique properties of the building blocks and additional intriguing collective properties derived from the interaction between adjacent NPs. However, the spontaneous assembly of inorganic NPs into 3D free-standing plasmonic superlattices still remains an enormous challenge. Herein, we report a facile and universal strategy to assemble gold nanoparticles (AuNPs) tethered with polystyrene (PS) and poly(2-vinylpyridine) (P2VP) homopolymers into 3D free-standing sheet-like superlattices by systematically tuning the oil/water interfacial tension and the interfacial instability of emulsion droplets. The prepared sheet-like superlattices are multilayer and the AuNP building blocks stack as tetrahedra, in which each AuNP building block is partially sitting on the three other nearby nanoparticles. Moreover, the interparticle distance between adjacent NPs can be effectively regulated by varying the molecular weight of the tethered PS ligands on the surface of AuNPs. This template-free approach provides a novel and effective route to manipulate nanoparticles into free-standing ordered 3D superlattices with a wide range of potential applications.

中文翻译：

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由乳液液滴的界面不稳定性驱动的金纳米粒子的自组装 3D 独立超晶格

由功能性无机纳米粒子 (NPs) 自组装的三维 (3D) 超晶格材料由于构建块的独特性质和源自相邻 NPs 之间相互作用的其他有趣的集体性质而引起了广泛关注。然而，将无机纳米粒子自发组装成 3D 独立等离子体超晶格仍然是一个巨大的挑战。在此，我们报告了一种简便而通用的策略，通过系统地调整油/水界面，将与聚苯乙烯 (PS) 和聚 (2-乙烯基吡啶) (P2VP) 均聚物相连的金纳米粒子 (AuNPs) 组装成 3D 独立的片状超晶格乳液液滴的张力和界面不稳定性。制备的片状超晶格是多层的，AuNP积木堆叠为四面体，其中每个 AuNP 构建块部分位于其他三个附近的纳米粒子上。此外，通过改变 AuNPs 表面上束缚的 PS 配体的分子量，可以有效地调节相邻 NPs 之间的粒子间距。这种无模板方法提供了一种新颖有效的途径来将纳米粒子操纵成独立的有序 3D 超晶格，具有广泛的潜在应用。