Synthesis of highly ordered mesoporous compounds with control of morphology using a non-ionic surfactant as template

摘要

Highly ordered hexagonal mesostructures (CMI-1 compounds) can be obtained under mild acidic conditions by working at low concentrations of non-ionic decaoxyethylene cetyl ether [C_(16)(EO)_(10)]. The present work shows that it is possible to gain control at the nanometer scale over the packing symmetry of the channels, as well as at the micrometer level over the morphology of the particles by varying the surfactant / silica molar ratio and the hydrothermal treatment conditions. Very high loadings of silica precursors typically afford highly ordered hexagonal CMI-1 compounds whereas an increase of the surfactant / silica molar ratio results in materials with a more disordered channel array. In a parallel way, very low molar ratios of surfactant / silica lead to ropes, gyroids and toroids whereas spheres are the most stable shape with the lower quantities of silica. From this point, it appears thus that not only the structure but also the morphologies encountered for MCM-41 type mesoporous silica can be reproduced with a non-ionic templating agent.