Since the gels prepared via solution processes inherently retain porosity, porous glasses are generally obtained as intermediate products to final full-dense glasses. In order to avoid undesired deformation and fracture on drying, various efforts have been made to control the drying behavior of wet gels through the precise control of their pore size distribution. Shoup  demonstrated the formation of meso- to macroporous alkali silicate gels which can be dried without fracture and sintered into full dense silica glass after vigorous washing. For more general alkoxy-derived gels, Hench et al.  established a process to enlarge the median pore size of silica by immersing gels into aqueous ammonium hydroxide solutions.
KeywordsPore Size Distribution Porous Glass Monolithic Column Ammonium Hydroxide Solution Median Pore Size
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