ABSTRACT
Surface treatment is important prior to chemical modification of silica gels. The effects of acid and base washing were studied using porous glass. Washing using sodium hydroxide solution was shown to be more effective than that using hydrochloric acid by comparison of the surface smoothness of porous glass in Figs. 2A-2C. Figure 2A is an electron micrograph of the original porous glass. The acid-washed, boiling porous glass using 6N hydrochloric acid, smoothed the edge of holes (Fig. 2B), and immersion in 6N sodium hydroxide solution solved the thin bridges (Fig. 2C). Furthermore, surface treatment using trichlorooctylsilane in toluene indicated that octyl groups were not homogeneously bonded to the surface of porous glass, as shown in Fig. 3, and octylsilane were bonded islandlike [44].
