Sun, YH (reprint author), Chinese Acad Sci, Inst Coal Chem, State Key Lab Coal Convers, POB 165, Taiyuan 030001, Peoples R China.
Small-angle X-ray scattering (SAXS) using synchrotron radiation as X-ray source has been employed to characterize the microscopic structure of organo-modified mesoporous molecular sieves (organo-MSU-X) prepared by a one-pot template-directed synthesis. It is shown that the SAXS profile is hardly constant with Pored's law showing a negative slope, i.e., negative deviation. This suggests that there is a diffuse interfacial layer located between the pores and the matrix. This suggests that the organic groups remain covalently linked to the matrix, as indicated by (SiCP)-Si-29 MAS NMR and FT-IR. The average thickness of the interfacial layer was found to be about 1 nm for each of the three samples with different kinds and the same amounts (20%) of organic groups. This kind of material has also been proved to possess both surface and mass fractal structures. The correction of the negative deviation from Pored's law is performed in order to obtain the pore structure of the amorphous porous silica materials. (C) 2001 Elsevier Science B.V. All rights reserved.