Hierarchical self-assembly in molecularly ordered phenylene-bridged mesoporous organosilica nanofilaments

Herein we report on the mechanism of formation of a hybrid phenylene-bridged hexagonally ordered mesoporous organosilica with crystal-like walls (CW-Ph-HMM). Electron microscopy and X-Ray diffraction studies indicate that the formation of CW-Ph-HMM involves the surfactant-mediated hydrothermal transformation of an amorphous organosilica precursor and that the final product is hierarchically ordered. Significantly, the material is in the form of submicrometre-thick sheets that consist of co-aligned aggregates of needle-like particles (up to 500 nm in length and 50 nm in width). The results suggest that preferential growth along the channel direction of the hexagonally ordered mesostructure is coupled with the propagation of molecular periodicity in the pore walls. Together, these factors give rise to the growth of highly anisotropic primary nanofilaments that become co-aligned to produce micrometer-thick sheets consisting of a periodic array of mesoscopic channels oriented perpendicular to the surface of the flake-like particles.