Chen Shu, Guo Chen, Hu Guo-Hua, Wang Jing, Ma Jun-He, Liang Xiang-Feng, Zheng Lily, Liu Hui-Zhou
Laboratory of Separation Science and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
Langmuir. 2006 Nov 7;22(23):9704-11. doi: 10.1021/la061093m.
In this paper we present the effect of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymer micelles and their hydrophobicity on the stabilization of gold nanoparticles. Gold nanoparticles were prepared by a method developed by Sakai et al. (Sakai, T.; Alexandridis, P. Langmuir 2004, 20, 8426). An absorption centered at 300-400 nm in time-dependent UV spectra provided evidence that the very first step of the synthesis was to form primary gold clusters. Then the gold clusters grew in size and were stabilized by block copolymer micelles. The stabilization capacities of the micelles were modulated by tuning the block copolymer concentration and composition and by adding salts. With good stabilization, gold particles were spherical and uniform in size with a diameter of 5-10 nm. Otherwise they were aggregates with irregular shapes such as triangular, hexagonal, and rodlike. The presence of a small amount of NaF significantly increased the stabilization capacity of the micelles and consequently modified the quality of the gold particles. Using FTIR and 1H NMR spectroscopy, micellization of the block copolymers and hydrophobicity of the micelles were proven very important for the stabilization. A higher hydrophobicity of the micelle cores was expected to favor the entrapment of primary gold clusters and the stabilization of gold nanoparticles.
在本文中，我们展示了聚（环氧乙烷）-聚（环氧丙烷）-聚（环氧乙烷）嵌段共聚物胶束及其疏水性对金纳米颗粒稳定性的影响。金纳米颗粒采用Sakai等人（Sakai, T.; Alexandridis, P. Langmuir 2004, 20, 8426）开发的方法制备。时间依赖紫外光谱中以300 - 400 nm为中心的吸收峰表明，合成的第一步是形成初级金簇。然后金簇尺寸增大，并由嵌段共聚物胶束稳定。通过调节嵌段共聚物浓度和组成以及添加盐来调控胶束的稳定能力。在良好的稳定条件下，金颗粒呈球形且尺寸均匀，直径为5 - 10 nm。否则它们会形成诸如三角形、六边形和棒状等不规则形状的聚集体。少量NaF的存在显著提高了胶束的稳定能力，从而改变了金颗粒的质量。利用傅里叶变换红外光谱（FTIR）和核磁共振氢谱（1H NMR）证实，嵌段共聚物的胶束化以及胶束的疏水性对稳定性非常重要。预计胶束核心更高的疏水性有利于捕获初级金簇并稳定金纳米颗粒。
