Ordered Structure Analysis of Prepared Mesoporous Silica Using Small Angle X-Ray Scattering

Abstract

O rdered pores structure analysis of mesoporous silica material s using a template of poly(ethylene oxyde)-poly(propylene oxide)-poly(ethylene oxide), PEO-PPO-PEO, triblock copolymer or Pluronics in numerous synthesis conditions has been conducted . Two different length of hydrophilic chain of Pluronics, i.e., P123 (EO 20 PO 70 EO 20 ) and F127 (EO 106 PO 70 EO 106 ), produced two different fine pore structures, which were basically hexagonal and cubic. A highly ordered pore structure, confirming with many Bragg peaks, was clearly obtained with the lattice parameters in nanometer scale from analyzing the synchrotron s mall a ngle X-ray scattering (SAXS) data . Meanwhile, the surface are a and pores size of mesoporous silica determined by nitrogen absorption clearly support the analysis of SAXS data, presenting a complete information of pore order characteristics. This paper shows how the synthesis parameters, such as length of hydrophilic chains, silica precursor concentration, Al:Si ratio and synthesis methods, are related to the structure and order of the pores formed. The SAXS patterns show that the pore order increases with increasing concentration of sodium silicate and decreases with longer sonication time. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Table Normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Times New Roman,serif; mso-ansi-language:EN-US; mso-fareast-language:EN-US;}