NANOSTRUCTURED ORGANIC-INORGANIC HYBRID MATERIALS SYNTHESIZED THROUGH SIMULTANEOUS PROCESSES

The sol-gel process, with its associated mild conditions, offers a new approach to the synthesis of composite materials with domain sizes approaching the molecular level. Both the organic and inorganic phases can be simultaneously formed through the synchronous polymerization of the organic monomer and the sol-gel precursors. Depending upon such factors as the structures of the organic and inorganic components, the phase morphology, the degree of interpenetration, and the presence of covalent bonds between the phases, the properties of these composites can vary greatly and range from elastomeric rubbers to high modulus materials. In an attempt to solve the truculent shrinkage problem historically associated with sol-gel derived glasses, we have synthesized tetraalkoxy orthosilicates possessing polymerizable alkoxide groups. The resultant alcohols, which are liberated during the hydrolysis and condensation steps associated with the formation of the inorganic component, are polymerized in-situ to form the organic phase of the composite material. The synthesis and mechanical properties of these nonshrinking hybrid materials will be discussed.