| Abstract
| - The pore variations of ordered cage-type mesoporous silica FDU-12s have been analyzed in detail by PXRD,SAXS, nitrogen sorption, and electron crystallography. FDU-12s with a cubic symmetry (space group, Fm3̄m)were templated by amphiphilic triblock copolymer F127 with the addition of 1,3,5-trimethylbenzene andKCl under an acidic condition. Three typical samples with different unit cell sizes, pore cage diamters, andentrance sizes were obtained from different synthesis and hydrothermal treatment temperatures, as indicatedby the differences in the PXRD and SAXS patterns. The pore structure changes in the three materials wereobserved by nitrogen adsorption/desorption and 3-D reconstruction of HRTEM images taken from differentcrystal orientations. The approximate pore structures of FDU-12s can be regarded as a face-centered cubic(fcc) close-packing of spherical cages, each connected to 12 nearest neigboring cages. However, the idealspherical model is only valid for the FDU-12s prepared at a low temperature (L-FDU-12-100). The cageshape of the FDU-12s synthesized at a high temperature deviates from perfect spheres and is accompaniedby an entrance enlargement. The temperature-dependent behavior of the PEO block is discussed with regardto its influence on the micelles and hence the cage configuration. The better understanding of the formationmechanism via the combined characterization techniques and modeling may lead to a more rational approachfor tuning the pore cages and entrances of the mesoporous FDU-12 materials.
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