经典stober法

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'经典stober法'
JOURNAL OF COLLOID AND INTERFACE SCIENCE 26, 62--69 (1968) Controlled Growth of Monodisperse Silica Spheres in the Micron Size Range 1 WERNER STOBER, ARTHUR FINK Department of Radiation Biology and Biophysics, Medical School, University of Rochester, New York 14620 A~D ERNST BOHN, Max-Planck-Institut fi~r experimentelle Medizin, GOttingen, Germany Received August 3, 1967 A system of chemical reactions has been developed which permits the controlled growth of spherical silica particles of uniform size by means of hydrolysis of alkyl silicates and subsequent condensation of silicie acid in alcoholic solutions. Ammonia is used as a morphological catalyst. Particle sizes obtained in suspension range from less than 0.05 t, to 2 ~ in diameter. In many experimental studies which in- volve the use of colloidal suspensions of matter in form of hydrosols and aerosols, it would be desirable to have the suspended phase consisting of homogeneous particles of uniform shape and size. Such monodisperse particulate suspensions offer many experi- mental and theoretical advantages. They not only facilitate easy calibration proce- dures for analytical equipment, but also simplify data reduction, evaluation and in- terpretation of experiments designed to elu- cidate physicoehemieal properties or physi- opathological effects of colloids and aerosols. The results would no longer be biased by parameters of size and shape distributions. Some monodisperse suspensions of parti- cles in the colloidal size range are available in form of spheres of organic high polymers (1). In the aerosol field, they are primarily used as model substances and for calibration purposes. Generators producing monodis- perse particle clouds from soluble or volatile materials are used in various aerosol studies I This paper is based in part on work performed under contract with the U.S. Atomic Energy Commission at the University of Rochester Atomic Energy Project and has been assigned Publication No. UR-49-815. and have been described in the literature (2). However, no successful attempt has been made to generate monodisperse suspen- sions of silica particles. A commercial form of highly disperse silica produced by com- bustion of silicon tetraehloride in a hydrogen torch (3) consists of primary silica spheres of sizes below 0.1 u, but they are aggregated to coarse and irregular clusters which cause a very poorly defined state of suspension. The following investigation was made to explore the possibilities of producing mono- disperse suspensions of silica spheres in the colloidal size range. Such material can be used in both hydrosol and aerosol studies. It will be of particular interest to investi- gators in the medical field because of its known eytotoxicity and inhalation hazard. The experiments were based on the fact that silica particles can be produced by chemical reaction of tetraesters of silicie acid (tetraalkyl silicates) with certain solu- tions. In 1956, Kolbe (4) described the formati
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经典 stober
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