QUIESCENT NON-IONIC SURFACTANT ASSEMBLY OF MESOPOROUS MATERIALS UNDER BASIC CONDITIONS

摘要

For the first time a polymer organized mesoporous silica material with the thick walls and the pores on the border between the micropore and mesopore region is prepared under quiescent and basic conditions, which is based on the homogeneous precipitation of silica due to the basic hydrolysis of ethyl acetate. Firstly, the synthetic parameters affecting the mesostructure were investigated. The hydrolysis rate of ethyl acetate plays the most important role in this procedure, which provides with protons to condensate silica species and controls the rate of silica polycondensation. Higher EtAc/Na_2SiO_3 ratio, higher ageing temperature than 313 K, or addition of anionic surfactant sodium dodecyl benzene sulfonate as co-surfactant will all result in fast condensation of silica species, which is unfavorable for the formation of mesostructures. And fluoride ions added at aging step has deleterious effect on the formation of the mesostructures because fluoride catalytically accelerates the polycondensation of silica species, while the introduction of fluoride ions during the hydrothermal treatment has a little influence. Finally the samples synthesized by this procedure were characterized by XRD, BET, TG-DSC and SEM.