Synthesis and characterization of water-soluble silsesquioxane-based nanoparticles by hydrolytic condensation of triethoxysilane derived from 2-hydroxyethyl acrylate.
Synthesis and characterization of water-soluble silsesquioxane-based nanoparticles by hydrolytic condensation of triethoxysilane derived from 2-hydroxyethyl acrylate.
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DOI：
10.1021/la700706a
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发表时间：
2007-07
期刊：
影响因子：
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通讯作者：
H. Mori;Yasushi Miyamura;T. Endo
中科院分区：
文献类型：
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作者：
H. Mori;Yasushi Miyamura;T. Endo
以丙烯酸羟乙酯为原料，通过三乙氧基硅烷前驱体R-Si(OCH2CH3)3，R=-CH2CH2CH2N(CH2CH2COOCH2CH2OH)2的水解缩合反应合成了一类新的倍半硅氧烷纳米粒子。在氢氟酸(HF)存在下，三乙氧基硅烷前驱体在甲醇中以均相体系的形式缩合，得到了基于倍半硅氧烷的水溶性纳米颗粒，其结构经核磁共振、红外光谱和元素分析证实。扫描力显微镜(SFM)测试表明，纳米粒子的尺寸分布较窄，平均粒径小于2.0 nm，无团聚现象。用X射线衍射仪测定了纳米粒子的大小(1.7 nm)。尺寸排阻色谱也证实了具有6-12个硅原子的物种的窄多分散性(MW/Mn=1.08)和合理的相对分子质量(Mn=3300)。将正硅酸乙酯(TEOS)与前驱体三乙氧基硅烷(TEOS)在不同进料比下进行共缩合反应，得到了TEOS摩尔比高达70%的水溶性产物。热重分析表明，随着原料中TEOS含量的增加，热稳定性和成炭率增加。在正硅酸乙酯/三乙氧基硅烷前驱体=50/50摩尔%时，用扫描电子显微镜观察到分离出的纳米粒子分布均匀，没有任何团聚现象。
A new family of silsesquioxane-based nanoparticles was synthesized by hydrolytic condensation of a triethoxysilane precursor, R-Si(OCH2CH3)3, R = -CH2CH2CH2N(CH2CH2COOCH2CH2OH)2, derived from 2-hydroxyethyl acrylate. Condensation of the triethoxysilane precursor proceeded as a homogeneous system in methanol in the presence of hydrofluoric acid (HF) to afford water-soluble silsesquioxane-based nanoparticles, as confirmed by NMR, FT-IR, and elemental analyses. Scanning force microscopy (SFM) measurements indicated the formation of nanoparticles having a relatively narrow size distribution with an average particle diameter of less than 2.0 nm without aggregation. The size of the nanoparticles (1.7 nm) was determined by X-ray diffraction (XRD). The narrow polydispersity (Mw/Mn = 1.08) and a reasonable molecular weight (Mn = 3300), corresponding to species having 6-12 silicon atoms, were also confirmed by size-exclusion chromatography. Co-condensation of tetraethoxysilane (TEOS) with the triethoxysilane precursor was carried out under different feed ratios, and water-soluble products were obtained in the cases of TEOS molar ratios up to 70%. Thermal stability and the char yield were found to increase with increasing TEOS content in the feed, as determined by thermogravimetric analysis. The isolated nanoparticles distributed homogeneously without any aggregation were visualized by SFM, when the product was prepared at TEOS/triethoxysilane precursor = 50/50 mol %.