Effect of solution chemistry and speciation on shelf-life of silica sols and characteristics of deposited mesoporous thin films.

The effects of storage temperature and time on deposition characteristics of molecularly templated silica sols, used in synthesis of mesoporous silica films, were investigated by preparing acid catalysed water-ethanol-TEOS sols with surfactant and analysing by silicon-29 NMR spectroscopy over a period of multiple days, and by producing films after specific storage times corresponding to collection of NMR spectral data, and analysed for thickness and porosity.

Selective sorption of cesium using self-assembled monolayers on mesoporous supports.

The synthesis of a novel nanocomposite sorbent material, copper ferrocyanide immobilized within a mesoporous ceramic matrix, and its use as a novel cesium sorbent material is reported in this paper. Complete removal of cesium was achieved in the presence of competing metal ions for solutions containing 2 ppm cesium under a variety conditions. Loading capacity of more than 1.35 mmol Cs per g of sorbent material has been achieved. The exceptionally fast binding kinetics and high loading capacity, resulting from the rigidly open pore structure and extremely high surface area of the sorbent materials, make them potentially very useful for the removal of cesium from nuclear wastes and contaminated groundwater.

X-ray absorption fine structure spectroscopy determination of the binding mechanism of tetrahedral anions to self assembled monolayers on mesoporous support.

X-ray absorption fine structure (XAFS) spectroscopy is used to investigate the chemical interaction between the end member [Cu(NH2)6] of self-assembled monolayers on mesoporous supports (SAMMS) and the tetrahedral anion SO4. The local structure about Cu indicates monodentate bonding between the SO4 anion and the SAMMS.

Surface-induced mineralization: a new method for producing calcium phosphate coatings.

Calcium phosphate coatings were nucleated and grown from aqueous solution onto titanium metal substrates via surface-induced mineralization (SIM) processing techniques. This process is based on the observation that in nature organisms use biopolymers to produce ceramic composites, such as teeth, bones, and shells. The SIM process involves modification of a surface to introduce surface functionalization followed by immersion in aqueous supersaturated calcium phosphate solutions. This low-temperature process (< 100 degrees C) has advantages over conventional methods of calcium phosphate deposition in that uniform coatings are produced onto complex-shaped and/or microporous samples. Additionally, because it is a low-temperature process, control of the phase and crystallinity of the deposited material can be maintained.

Ceramic thin-film formation on functionalized interfaces through biomimetic processing.

Processing routes have been developed for the production of thin ceramic films through precipitation from aqueous solutions. The techniques are based on crystal nucleation and growth onto functionalized interfaces. Surface functionalization routes have been developed by the mimicking of schemes used by organisms to produce complex ceramic composites such as teeth, bones, and shells. High-quality, dense polycrystalline films of oxides, hydroxides, and sulfides have now been prepared from "biomimetic" synthesis techniques. Ceramic films can be synthesized on plastics and other materials at temperatures below 100 degrees C. As a low-temperature process in which water rather than organic solvents is used, this synthesis is environmentally benign. Nanocrystalline ceramics can be produced, sometimes with preferred crystallite orientation. The direct deposition of high-resolution patterned films has also been demonstrated. The process is well suited to the production of organic-inorganic composites.

The nucleation and growth of calcium oxalate monohydrate on self-assembled monolayers (SAMS).

A physical chemical approach was used to study calcium oxalate monohydrate (COM) nucleation and growth on various organic interfaces. Self-assembling monolayers (SAMs), containing derivatized organic functional groups, were designed to mimic various amino acid residues present in both urine and stone matrix macromolecules. Derivatized surfaces include SAMs with terminal methyl, bromo, imidazole, and thiazolidine-carboxylic acid functional groups. Pronounced differences in COM deposition were observed for the various interfaces with the imidazole and thiazolidine surfaces having the greatest effect and the methyl and bromo groups having little or no nucleating potential.