(100d) One-Pot Synthesis of Functional Mesoporous Materials

Mesoporous silicas can be obtained from the self-assembly of amphiphilic building blocks in the presence of pure silica or organosilica precursors. Solvent-extraction of the soft organic template leads to a periodic ordered mesoporous material. Such materials find application in several industrial fields, and are especially important in adsorption and catalysis. Functional groups can be added to the porous framework through a post synthesis treatment, or included in the framework at the time of the synthesis itself. The former has the advantage that the structure of the framework is known prior to adding the functional groups, while the latter has the advantage of a reduced number of steps in the synthesis procedure. One of the disadvantages of the one-pot synthesis method is that high quality materials cannot be obtained using pure organosilica precursors, and often mixtures of pure silica and organosilica precursors are used.

In this work, lattice Monte Carlo simulations in the NVT ensemble have been performed to study the formation of mesoporous materials containing functional organic groups into their pore walls. Four components systems, composed by a surfactant, a pure silica precursor, an organosilica precursor, and a simple solvent, have been studied. Different organosilica precursors have been modeled in order to establish to which extent they affect or transform the original surfactant mesophases. In particular, we observe that small functional groups can lead to the destruction of hexagonally ordered phases obtained with pure silica precursors, while sufficiently large solvophobic functional groups can transform hexagonal phases into lamellar phases.