Leibniz Institute for New Materials, Structure Formation group and Nano Cell Interaction group, Campus D2 2, 66123 Saarbruecken, Germany.
Langmuir. 2011 Jan 18;27(2):727-32. doi: 10.1021/la102630y. Epub 2010 Dec 13.
We report the synthesis of well-dispersed core-shell Au@SiO(2) nanoparticles with minimal extraneous silica particle growth. Agglomeration was suppressed through consecutive exchange of the stabilizing ligands on the gold cores from citrate to L-arginine and finally (3-mercaptopropyl)triethoxysilane. The result was a vitreophilic, stable gold suspension that could be coated with silica in a biphasic mixture through controlled hydrolysis of tetraethoxysilane under L-arginine catalysis. Unwanted condensation of silica particles without gold cores was limited by slowing the transfer across the liquid-liquid interface and reducing the concentration of the L-arginine catalyst. In-situ dynamic light scattering and optical transmission spectroscopy revealed the growth and dispersion states during synthesis. The resulting core-shell particles were characterized via dynamic light scattering, optical spectroscopy, and electron microscopy. Their cores were typically 19 nm in diameter, with a narrow size distribution, and could be coated with a silica shell in multiple steps to yield core-shell particles with diameters up to 40 nm. The approach was sufficiently controllable to allow us to target a shell thickness by choosing appropriate precursor concentrations.
我们报告了具有最小外来二氧化硅颗粒生长的分散良好的核壳 Au@SiO(2)纳米粒子的合成。通过连续将金核上的稳定剂从柠檬酸盐交换为 L-精氨酸，最后交换为（3-巯丙基）三乙氧基硅烷，抑制了团聚。结果得到了亲玻璃的、稳定的金悬浮液，通过在 L-精氨酸催化下控制四乙氧基硅烷的水解，可以在两相混合物中用二氧化硅进行涂层。通过减缓穿过液-液界面的转移和降低 L-精氨酸催化剂的浓度，限制了没有金核的二氧化硅颗粒的不必要缩合。原位动态光散射和光透射光谱揭示了合成过程中的生长和分散状态。通过动态光散射、光谱学和电子显微镜对所得核壳粒子进行了表征。它们的核通常为 19nm 直径，具有较窄的尺寸分布，可以通过多次涂覆二氧化硅壳来制备直径高达 40nm 的核壳粒子。该方法具有足够的可控性，可通过选择合适的前体浓度来控制壳层厚度。
