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 u npolymerized, hexagonal, lyotropic silicate-surfactant liquid crystal in a high magnetic field. This alignment was preserved after polymeriz ation of the silicate species by acid treatment, Subsequent calcinatio n to remove the surfactant yielded a mesoporous silica solid that reta ined both macroscopic pore alignment and mesoscale periodicity. Potent ial applications of such liquid crystal processing strategies range fr om the formation of anisotropic silica-based bulk ceramics to the prod uction of oriented mesoporous thin films for chemical sensors, separat ions, catalysis, or host-guest applications.