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 of mesoporous silica prepared by one-pot template-directed synthesis methodology. The scattering of pure silica agreed with Porod's law. The scattering of organo-modified mesoporous silica showed a negative deviation from Porod'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 resonance imaging (Si-2(9) CP MASNMR) and Fourier transform infrared spectroscopy (FTIR), that caused this negative deviation of SAXS intensity from Porod's law, and the average thickness of the interfacial layer could be deduced from this negative deviation. Copyright (C) 2001 John Wiley & Sons, Ltd.