Monte Carlo simulations of self-assembling hexagonal and cage-like bifunctional periodic mesoporous materials

Self-assembly of lyotropic liquid crystalline mesophases formed by amphiphilic molecules was studied using computer simulations. The addition of an inorganic and two hybrid organic-inorganic precursors, one with a bridging and the other with a terminal organic functionality, lead to the formation of bifunctional hexagonally-packed mesoporous materials. These structures exhibit very ordered and uniform mesopores with the organic functional groups located in the cylindrical pores and in their walls, and are found to be stable over a relatively broad range of precursor concentrations. Hexagonal-to-lamellar and hexagonal-to-cubic phase transitions have been observed at constant surfactant concentrations by tuning the relative content of the hybrid precursors which modify the overall solvophilic character of the solvent and, as a consequence, the surfactant solubility in its surrounding environment. The long range ordered cubic phases show interconnected, roughly spherical mesocages of uniform size and an interesting distribution of the organic functionalities.