SAXS analysis of interface in organo-modified mesoporous silica

A small-angle x-ray scattering (SAXS) technique using synchrotron radiation as the x-ray source has been employed to characterize the microstructure o f mesoporous silica prepared by one-pot template-directed synthesis methodo logy. The scattering of pure silica agreed with Porod's law. The scattering of organo-modified mesoporous silica showed a negative deviation from Poro d's law, suggesting that an interfacial layer exists between the pores and silica matrix. It was the organic groups comprising the interface, as shown by Si-29 cross-polarization magic-angle spinning nuclear magnetic resonanc e imaging (Si-2(9) CP MASNMR) and Fourier transform infrared spectroscopy ( FTIR), that caused this negative deviation of SAXS intensity from Porod's l aw, and the average thickness of the interfacial layer could be deduced fro m this negative deviation. Copyright (C) 2001 John Wiley & Sons, Ltd.