Inorganic-Organic Molecular Bonding in Porous Matrices

摘要

The use of porous gel-silica matrices as host materials for optical sensors,catalyst supports, and organic-inorganic composite materials has received increased attention over the past several years. Porous, optically transparent hosts have several advantages over traditional materials for these applications. Large surface areas inherent in sol-gel derived silica increase the interaction area for surface mediated reactions while large pore volumes enhance the introduction of organic or inorganic modifiers or analyzates into the glass substrate. The ability to produce larger pores in these materials increases the permeability and environmental stability of the substrates and enhances the introduction of second phases as modifiers. Greater permeability also increases the responsiveness of sensors and efficiencies of catalyst materials. Previous efforts have produced and characterized gel-silica matrices with average pore diameters from 2.4nm to 20nm. With recent advances, gel-silica matrices have now been fabricated with average pore diameters as large as 80nm using conventional drying techniques. The introduction of CO2 supercritical drying of matrices has enhanced the ability to specifically tailor the surface area and pore volume. The feasibility of doping with metal salts and colloids has been demonstrated as well as the ability to produce dense silica optical components.