Casting Silica at Room Temperature Silica cannot be used with traditional molding techniques because of its very high melting temperature. In addition, conventional grinding and polishing processes limit how small and complex the silica micro-optics can be. Geltech overcame these problems by developing methods to cast net-shape (no grinding necessary) silica-glass micro-optics at room temperatu...

A new atomic layer deposition (ALD) process was applied for the uniform coating of carbon nanotubes with a number of transition-metal oxide thin films (vanadium, titanium, and hafnium oxide). The presented approach is adapted from non-aqueous sol-gel chemistry and utilizes metal alkoxides and carboxylic acids as precursors. It allows the coating of the inner and outer surface of the tubes with ...

Although transfer of electrophilic alkoxyl ("RO+") from organic peroxides to organometallics offers a complement to traditional methods for etherification, application has been limited by constraints associated with peroxide reactivity and stability. We now demonstrate that readily prepared tetrahydropyranyl monoperoxyacetals react with sp(3) and sp(2) organolithium and organomagnesium reagents...

By manipulating polymerization conditions in solution precursors, it is possible to control the structure of silica aerogels. Porosity varies from grain-like to polymer-like. When produced from alkoxides, pH is the dominant factor that determines structure. Under strongly basic conditions (pH > 12) compact colloidal particles are observed. In the range pH = 8-12, particles of varying surface ro...

There is a great deal of interest in continuous beds as stationary phases for both HPLC and CEC. There are various ways to prepare monoliths, by polymerization of organic species or by polymerization of silicon alkoxides. The former method has recently been reviewed, while silica based monoliths are now commercially available. The purpose of this paper is to deal with the problems associated wi...

The invention of electrospinning has solved the problem of producing micro- and nanoscaled metal oxide fibres in bulk quantities. However, until now no methods have been available for preparing a single nanofibre of a metal oxide. In this work, the direct drawing method was successfully applied to produce metal oxide (SnO2, TiO2, ZrO2, HfO2 and CeO2) fibres with a high aspect ratio (up to 10 00...

Sol–gel derived Bi2Ti2O7 ceramic powders have been prepared from methoxyethoxides of bismuth and titanium (molar ratio of Ti/Bi = 1.23 and water/alkoxides= 1.31). The Bi2Ti2O7 phase was stable at a low temperature (700 ◦C), but it then transformed into mixed phases of Bi4Ti3O12 and Bi2Ti4O11 at 850–1150 ◦C. The single phase of Bi2Ti2O7 reoccurred at 1200 ◦C. Dielectric properties and ferroelect...

In this study the effects of the nature of metal alkoxides on their vapour pressures and thermal decomposition chemistry are reported. The vapour pressure and the volatility of a metal alkoxide strongly depends on the steric effect of its alkoxy group. The thermal decomposition chemistry of one metal alkoxide (di-acetoxy-di-t-butoxysilane, DADBS) has been studied by mass spectrometry at tempera...