| This work describes the creation and analysis of ordered porous inorganic and organic-inorganic hybrid materials with an emphasis on the qualitative and quantitative characterization by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Two major systems were studied: MCM-41-type mesoporous molecular sieves and three-dimensionally ordered macroporous (3DOM) materials.; The microanalysis of mesoporous samples is discussed first. Samples of unmodified siliceous MCM-41, MCM-41 with grafted titanium dioxide species, and MCM-41 with incorporated 3-mercaptopropyl groups were examined in the TEM at three accelerating voltages. The beam stability of all the samples increased with increasing accelerating voltage. The particles were significantly more resistant to beam damage with the surfactant template in place, when the samples were synthesized above room temperature, and when the silicate precursor was hydrolyzed in acid. The samples with organic and inorganic groups were more stable than siliceous analogs.; The discussion of 3DOM materials begins with their synthesis and characterization: 3DOM materials were created from colloidal crystals of uniform, sub-micrometer diameter polystyrene and poly(methyl methacrylate) spheres. Metal alkoxides, solutions of metal salts, and mixed salt-alkoxide precursors were employed to create 3DOM metal oxides, silicates with incorporated organic groups and polyoxometalate clusters, metals, and metal alloys. SEM and TEM were used extensively to characterize the morphology, crystallinity, grain size, and phase of the 3DOM products. The formation of 3DOM nickel oxide was studied by heating a nickel oxalate-colloidal crystal composite in an environmental SEM. The growth of the grains in 3DOM cobalt metal and 3DOM iron oxide were observed by high-temperature TEM. The arrangement of the pores in 3DOM materials was studied by analyzing diffractograms of TEM images of single particles tilted into different orientations. Metallic 3DOM products were examined by TEM. Images of 3DOM cobalt and nickel produced by calcination in flowing nitrogen showed grains surrounded by layers of carbon. Next, a potentially useful sensor material is introduced: the 3DOM oxides of silicon, aluminum, and zirconium were used to demonstrate a predictable and tailorable color change when saturated with fluids of various refractive indices. Finally, some future uses of 3DOM materials are considered. |
