SYNTHESIS AND CHARACTERIZATION OF MONODISPERSE COLLOIDAL ORGANO-SILICA SPHERES
SYNTHESIS AND CHARACTERIZATION OF MONODISPERSE COLLOIDAL ORGANO-SILICA SPHERES
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DOI：
10.1006/jcis.1993.1073
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发表时间：
1993-03-01
影响因子：
9.9
通讯作者：
VRIJ, A
中科院分区：
文献类型：
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作者：
VANBLAADEREN, A;VRIJ, A
单分散，胶体二氧化硅球制备由四乙氧基硅烷（TES）在氨，水和乙醇的混合物。颗粒的表面可以通过随后与硅烷偶联剂3-氨丙基三乙氧基硅烷（APS）的化学反应来涂覆。此外，一种新的单分散，胶体二氧化硅球（有机硅球），从APS和TES的混合物开始制备。用等量的APS和TES合成的有机硅球中，APS的含量高达总含量的37%。颗粒所占的量以及因此颗粒性质取决于醇盐混合物的初始组成。有人认为，最重要的反应，APS被纳入到颗粒是通过一个醇生产缩合反应与硅醇基团键合到一个硅原子，这是一个TES分子的一部分。由于提出的这种机制，有人认为，这种碱催化的方法，使混合有机二氧化硅颗粒也将适用于其他有机醇盐的混合物。有机硅微球与单独使用TES制备的硅微球在以下方面不同：水、氨和乙醇的混合物中的负表面电荷减少，质量密度较低（例如，1.51 g/cm 3相比于1.98 g/cm 3），微孔率更大，并且硅氧烷结构更少缩合。颗粒折射率较高，但差异较小（约0.02）。结果表明，表面有APS的颗粒可以通过TES制备的二氧化硅层长大。有机二氧化硅颗粒和二氧化硅涂覆的有机二氧化硅颗粒用硬脂醇进行表面涂覆。评估了所得在几种溶剂中的稳定性。不同的胶体系统，其特征在于静态和动态光散射，透射电子显微镜，元素分析，氮吸附测量，电泳，和qualitative 13 C和quantitative 19 Si固态核磁共振光谱。
Monodisperse, colloidal silica spheres were prepared from tetraethoxysilane (TES) in mixtures of ammonia, water, and ethanol. The surface of the particles could be coated through a subsequent chemical reaction with the silane coupling agent 3-aminopropyltriethoxysilane (APS). Also, a new kind of monodisperse, colloidal silica spheres (organo-silica spheres) was prepared starting from mixtures of APS and TES. Organo-silica spheres synthesized with equal amounts of APS and TES were found to contain as much as 37% of the total amount of APS. The amount taken up by the particles, and therefore also the particle properties, depended on the initial composition of the mixture of alkoxides. It is argued that the most important reaction by which APS is incorporated into the particles is through an alcohol-producing condensation reaction with a silanol group bonded to a silicon atom that was part of a TES molecule. Because of this proposed mechanism, it is argued that this base-catalyzed method of making hybrid organic-silica particles will also be applicable to mixtures of other organoalkoxides. The organo-silica spheres differed from silica spheres prepared with TES alone in the following aspects: The negative surface charge in the mixture of water, ammonia and ethanol was reduced, the mass density was lower (e.g., 1.51 g/cm3compared to 1.98 g/cm3), the microporosity was larger, and the siloxane structure was less condensed. The particle refractive index was higher, but the differences were small (around 0.02). It was shown that particles with APS on the surface could be grown larger with a silica layer prepared from TES. Organo-silica particles and silica-coated organo-silica particles were surface coated with stearyl alcohol. The resulting stability in several solvents was assessed. The different colloidal systems were characterized by static and dynamic light scattering, transmission electron microscopy, elemental analysis, nitrogen adsorption measurements, electrophoresis, and qualitative13C and quantitative19Si solid-state nuclear magnetic resonance spectroscopy.