Macro/mesoporous silica material

Because of the attractive physicochemical properties and potential applications in catalysis, biotechnology, adsorption, and separation, fabrication of hierarchically porous (macro/mesoporous) materials, especially for the three-dimensional ordered macro/ mesoporous (3DOM) materials, has been a focus in the research on materials science and engineering in recent years [99,199,200], By using close-packed arrays of monodisperse spheres, such as polystyrene (PS), poly(methyl methacrylate) (PMMA), and silica as template, metals [201,202], metal oxides [203-208], metal chalcogenides [209], silica [204,210,211], carbon [212,213], polymers [214,215], and hydroxyapatite [216] with 3DOM structures have been generated. 

Crosslinked vanadia aerogels underline the importance of the network morphology in the mechanical behavior of crosslinked aerogels. But vanadia is expensive. Bicontinuous macro/mesoporous materials consisting of entangled worm-Uke nanostmctures perforated by tubular mesopores (Figure 13.15A, B) have been created with acid-catalyzed silica by modification of Nakanishi s procedure [73], which in turn comprises a modification of... 

Villota R, Hawkes JG (1986) Food applications and the toxicological and nutritional implications of amorphous silicon dioxide. Crit Rev Food 8ci Nutr 23(4) 289-321 Wu Z, Jiang Y, Kim T, Lee K (2007) Effects of surface coating on the controlled release of vitamin B1 from mesoporous silica tablets. J Control Release 119 215-221 Zhang J, Yua J, Liub 8, Yana M, Zanga D, Gaoa L (2012) Controlled release of volatile menthol in nanoporous silica materials. J Incl Phenom Macro Chem 71 593-602... 

HMC is a very interesting porous carbon material with unique hierarchical macro/mesoporous spherical morphology. HMCs with various core sizes and/or shell thicknesses can be fabricated through the independent control of the core sizes and/or shell thicknesses of the SCMS silica templates [28,62,63], while the micro- and mesoporosity of the HMCs can be controlled to some extent by the source type and amount of carbon precursor incorporated into the SCMS silica template. HMC with different core shapes (non-spherical) have been synthesised through nanocasting techniques [61,64], A key factor for the s)mthesis of HMCs with diverse shapes and sizes lies in the fabrication of SCMS silica replica templates. 

This method allows independent control over both the macropores, which are determined by the emulsion droplets in the first step of the process, and the mesopores, by the supramolecular self-assembly in the second step. Therefore, the two templating systems do not interfere vhth each other, and consequently the meso-and macro-structures can be optimized separately [21]. Inorganic oxides, such as silica, titania and zirconia, were obtained by this two-step process. The bimodal distribution of pores was characterized by highly ordered mesopores (5-10 nm) and by interconnected macropores (0.1 to 5 p,m). These materials possess high pore volumes (17 cm g ) and specific surface areas, as determined by the BET method applied to the nitrogen adsorption isotherm, of between 250 and 750 The... 

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