Phenylene-bridged mesoporous organosilica films with uniaxially aligned mesochannels

The alignment of mesochannels in a phenylene-bridged mesoporous organosilica film is successfully controlled by using a substrate with a rubbing-treated polyimide film. The films are prepared by two different procedures: the hydrothermal deposition process and the so-called evaporation-induced self-assembly process. The narrow alignment distribution of mesochannels is achieved by the interfacial hydrophobic interactions between alkyl chains of surfactant and the elongated polymer chains of rubbing-treated polyimide. The molecular-scale ordering of the framework in the films is low, unlike those in mesoporous organosilica powders and films prepared under basic conditions, though the thickness of the pore walls is comparable to the molecular size. The emission behaviour in the ultraviolet region, which is sensitive to inter-phenylene interactions, is influenced by synthesis and thermal treatment temperatures, irrespective of the preparative methods. The changes in the spectra indicate that the major emissive species changes from the excited monomer to the excimer with the increase of temperature. These organic-inorganic hybrid films will find various applications by combining functionalities of organic and inorganic moieties and highly controlled nanospaces.