A negative deviation from Porod's law in SAXS of organo-MSU-X

✍ Scribed by Z.H. Li; Y.J. Gong; D. Wu; Y.H. Sun; J. Wang; Y. Liu; B.Z. Dong

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 95 KB
• Volume: 46
• Category: Article
• ISSN: 1387-1811
• DOI: 10.1016/s1387-1811(01)00292-x

✦ Synopsis

Small-angle X-ray scattering (SAXS) using synchrotron radiation as X-ray source has been employed to characterize the microscopic structure of organo-modi®ed mesoporous molecular sieves (organo-MSU-X) prepared by a one-pot template-directed synthesis. It is shown that the SAXS pro®le is hardly constant with Porod's law showing a negative slope, i.e., negative deviation. This suggests that there is a diuse interfacial layer located between the pores and the matrix. This suggests that the organic groups remain covalently linked to the matrix, as indicated by 29 SiCP 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 dierent 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 Porod's law is performed in order to obtain the pore structure of the amorphous porous silica materials.