Science, Vol.278, No.5336, 264-268, 1997
Magnetic-Field Alignment of Ordered Silicate-Surfactant Composites and Mesoporous Silica
Macroscopic orientational ordering of the pores of condensed hexagonal mesostructured silica (MCM-41) was achieved through alignment of an unpolymerized, hexagonal, lyotropic silicate-surfactant liquid crystal in a high magnetic field. This alignment was preserved after polymerization of the silicate species by acid treatment, Subsequent calcination to remove the surfactant yielded a mesoporous silica solid that retained both macroscopic pore alignment and mesoscale periodicity. Potential applications of such liquid crystal processing strategies range from the formation of anisotropic silica-based bulk ceramics to the production of oriented mesoporous thin films for chemical sensors, separations, catalysis, or host-guest applications.
Keywords:OXIDE MOLECULAR-SIEVES;LIQUID-CRYSTAL;MESOSTRUCTURAL MATERIALS;STRUCTURE ORGANIZATION;WATER-INTERFACE;H-2 NMR;LYOMESOPHASES;FILMS;ASSEMBLIES;POLYANIONS