Institut für Physikalische Chemie I: Kolloide und Nanooptik, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.
Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.
J Phys Chem B. 2021 Jul 29;125(29):8225-8237. doi: 10.1021/acs.jpcb.1c03772. Epub 2021 Jul 14.
Stabilization of gold nanoparticles in organic solvents is a key challenge in making them available for a wider range of material applications. Polymers are often used as stabilizing ligands because they also allow for the introduction of new properties and functionalities. Many of the established synthesis protocols for gold nanoparticles are water-based. However, the insolubility of many synthetic polymers in water renders the direct functionalization of aqueous particle dispersions with these ligands difficult. Here, we report on an approach for the functionalization of gold nanoparticles, which were prepared by aqueous synthesis, with hydrophobic polymer ligands and their characterization in nonpolar, organic dispersions. Our method employs an auxiliary ligand to first transfer gold nanoparticles from an aqueous to an organic medium. In the organic phase, the auxiliary ligand is then displaced by thiolated polystyrene ligands to form a dense polymer brush on the particle surface. We characterize the structure of the ligand shell using electron microscopy, scattering techniques, and ultracentrifugation and analyze the influence of the molecular weight of the polystyrene ligands on the structure of the polymer brush. We further investigate the colloidal stability of polystyrene-functionalized gold nanoparticles in various organic solvents. Finally, we extend the use of our protocol from small, spherical gold nanoparticles to larger gold nanorods and nanocubes.
在有机溶剂中稳定金纳米粒子是将其应用于更广泛的材料应用的关键挑战。聚合物通常被用作稳定剂，因为它们还可以引入新的性质和功能。许多已建立的金纳米粒子合成方案都是基于水的。然而，许多合成聚合物在水中的不溶性使得这些配体难以直接对水相颗粒分散体进行功能化。在这里，我们报告了一种在非极性有机分散体中对通过水相合成制备的金纳米粒子进行疏水性聚合物配体功能化的方法及其表征。我们的方法采用辅助配体首先将金纳米粒子从水相转移到有机介质中。在有机相中，然后用巯基化聚苯乙烯配体取代辅助配体，在颗粒表面形成致密的聚合物刷。我们使用电子显微镜、散射技术和超速离心法来表征配体壳的结构，并分析聚苯乙烯配体的分子量对聚合物刷结构的影响。我们进一步研究了聚苯乙烯功能化金纳米粒子在各种有机溶剂中的胶体稳定性。最后，我们将我们的方案从小的、球形金纳米粒子扩展到更大的金纳米棒和纳米立方体。
