Atomistic Model of Realistic Crystalline Mesoporous Organosilica Materials Including Nanochannels

The new class of periodic mesoporous organosilica materials (PMOs), due to the peculiar features, has attracted growing interest from several research areas. We present an atomistic model of a p-phenylenesilica crystalline mesoporous structure with a hexagonal framework, explicitly including channels on nanoscale. OPLS-AA force-field optimization, to get a suitable PMO structure compared with the experimental one, is described. In particular, DFT calculations have been performed to calculate torsional energy barrier of phenyl rings connected to the silicon atoms belonging to inorganic layers and to improve the OPLS-AA force field performances for these materials. Finally, inclusion of small molecules and their interactions with PMO walls have been investigated for CO2 and H2O.