Mesostructure Assembly System Interaction Mechanisms between Organics and Inorganics

1 Mesostructure Assembly System Interaction Mechanisms between Organics and Inorganics 

The synthesis mixture for mesoporous materials contains four major components inorganic precursors, organic template molecules, solvent, and acid or base catalyst. The formation of a material with a desired stmcture and morphology depends on a delicate interplay between several basic processes, whose relative rates determine the 

The typical synthesis of mesoporous material can be divided into two main stages (i) Formation of the organic-inorganic liquid-crystal phase (mesophases or mesostructure) results from the self-assembly of surfactant molecules and inorganic species which are polymerizable (or condensable) under synthesis conditions. Moreover, this mesostructure has a crystal lattice with the cell length in the nanometer range, (ii) Removal of surfactant from the mesostructure by calcination at high temperatures or other physical or chemical treatments results in the formation of mesopores (the space occupied by surfactant molecules) in the mesostructure. 

The surfactant may be cationic, or anionic, even nonionic. The type most used for MCM-41 and MCM-48 is cationic quaternary ammonium surfactant. The inorganic resources are those monomers or oligomers that are polymerizable or condensable under certain conditions (concentration, temperature, pressure, pH, solvent, etc.) and form inorganic solid matter such as gel, ceramic, and glass. The depolymerization or hydrolysis is necessary sometimes, for example with TEOS, Ti(OC2H5)4, silicon sol, sodium silicate, and amorphous silica. 

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