Well-ordered mesostructured silica and titania films were prepared using poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer species (Pluronic P123) as the structure-directing agents. By varying the volume ratio between the copolymer and inorganic components of the precursor solution, silica and titania thin films with cubic, 2D hexagonal, and lamellar mesostructures were prepared. The regions over which the three phases were obtained correspond well with those of the water-block copolymer binary phase diagram when considered in terms of the volume fraction of copolymer incorporated. In particular, a cubic mesostructure with crystalline TiO 2 (anatase) in the walls, stable to 400 °C, was synthesized.

Control over morphology and internal mesostructure of surfactant templated silicas remains a challenge, especially when considering scaling laboratory syntheses up to industrial volumes. Here we report a method combining emulsification with the evaporation-induced self-assembly (EISA) method for preparing spherical, mesoporous silica particles. This emulsion and solvent evaporation (ESE) method has several potential advantages over classic precipitation routes: it is easily scaled while providing superior control over stoichiometric homogeneity of templating surfactants and inorganic precursors, and particle sizes and distributions are determined by principles developed for manipulating droplet sizes within water-in-oil emulsions. To demonstrate the method, triblock copolymer P104 is used as a templating amphiphile, generating unusually well-ordered 2D hexagonal (P6mm) mesoporous silica, while particle sizes and morphologies were controlled by varying the type of emulsifier and the method for emulsification.

Thin films of bicontinuous cubic mesostructured silica were formed using the nonionic poly(oxyethylene)- alkyl ether surfactant Brij-56 as a structure-directing agent. The synthesis conditions were chosen such that the estimated volume fraction of surfactant in the silica/surfactant films corresponded approximately to the composition at which the bicontinuous cubic phase occurs in the water/surfactant phase diagram. Small-angle X-ray scattering and transmission electron microscopy measurements reveal that the cubic phase corresponds to the Ia3̄d double-gyroid structure, with some distortion due to anisotropic film shrinkage. The cubic structure grows as faceted domains that are well-oriented with respect to the substrate and often occur in coexistence with a lamellar phase. By adjusting the temperature at which the films are aged, it is possible to create films with 2D hexagonal, cubic, or lamellar structures at a single composition.

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Polystyrene (PS) colloidal particles have been used as templates to produce ordered macroporous silica structures. The silica films were deposited from ethanol solution containing acidic water and tetraethyl orthosilicate. The silica-coated PS spheres were characterized using transmission electron microscopy, and the film thickness determined by scanning electron microscopy and calculated from the relative weight of silica remaining after calcination. We found that the thickness of the silica film increased rapidly with time and reached a maximum that varied from 40 to 15 nm at pH 1.5 and 3, respectively. The data could be fitted to a simple first-order equation and the reaction rate and maximum thickness were related to the hydrolysis and condensation rate, respectively. Ordered macroporous structures were formed by centrifuging silica-coated PS spheres. Calcination of the close-packed spheres yielded a continuous silica matrix consisting of a threedimensional well-ordered network of monodisperse pores.

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The facile preparation of a mesoporous magnetic carrier technology is demonstrated. The micronsized spherical mesostructured particles are prepared using a newly-developed, one-step, combined emulsion and solvent evaporation (ESE) method. The surfactant-templated silica matrix display a well-ordered internal pore architecture. Very limited pore blocking, and only to a limited degree disordered-or worm-like structures are observed, induced by the iron oxide nanoparticles added to provide the superparamagnetic properties.The iron oxide content was precisely controlled, and the magnetic properties were well preserved during the process. Finally we demonstrate the applicability of the magnetically separable mesoporous material as an adsorbent for specific dissolved materials from dilute aqueous solutions.

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