New way to synthesize MCM-41 and MCM-48 materials with tailored pore sizes

The present work shows that by adjusting the molar ratio of two swelling agents : decane and TMB, the crystallization temperature and time, either the large pore hexagonal Si-MCM-41 or cubic Si-MCM-48 can be obtained. The characterization of these two structures by SEM, TEM, nitrogen adsorption-desorption analysis is reported. Their thermal stability has been also evaluated. It has been found that the decane and TMB concentration and the crystallization temperature can affect strongly the final structure of the products. The phase transition of cubic MCM-48 to hexagonal MCM-41 with increasing of TMB or decane concentration is explained by considering the surfactant packing parameter g (V/aslc). However, to explain the MCM-41 to MCM-48 transition with increasing crystallization temperature, some complementary studies should be made.