Preparation And Modification Of Micron Monodisperse Silica Microspheres And Its Application In Liquid Chromatography

Monodisperse silica spheres are widely used in anti-reflective coating materials, biomedicine, catalyst supports, photonic crystals and chromatographic packings. Size, monodispersity and surface properties of the microspheres have a broad impact on its application. The demand of size-controlled, good appearance and monodispersity silica spheres continued to increase. Because the properties of the microspheres changes with the particle size distributions, preparing monodisperse microspheres gradually attracted people’s attention.There are many ways for the preparation of monodisperse silica particles, such as liquid phase and vapor method, of which the most classic method is the sol-gel method(also called St?ber method), but St?ber method is usually used for the synthesis of submicron monodisperse silica spheres, for the larger particle size silica spheres, there are many synthesis problems. This paper improved the sol-gel method, the TEOS was dissolved in ethanol, and then was added dropwise to a solution containing the potassium chloride, water, ammonia, and ethanol, successfully prepared a diameter of 1~2 μm monodisperse silica microspheres. the effects of different reaction conditions on the particle size and the monodispersity of the silica, the results showed that, with the increasing of ammonia amount and dropping speed, the decreases on temperature and TEOS amount, silica microsphere particle size decreases, and the monodisperse better.The silica microspheres performance can be improved after surface modification, and the applications expanded. The general method of modifying divided into physical modification, chemical modification and physical chemistry synchronous modification. In this paper, by the method of chemical modification, we modified octadecyltrichlorosilane to the silica microspheres surface, and successfully applied to the chromatographic for the separation of fullerenes, due to the small size of the microspheres, the good monodispersity, high column efficiency, the use of stainless steel as short as 5 cm length will get a good separation of fullerenes. Better efficiency than the large particle size, ordinary long column length.