DESIGN OF HYBRID ORGANIC-INORGANIC MATERIALS SYNTHESIZED VIA SOL-GEL CHEMISTRY

Hybrid organic-inorganic networks are multifunctional materials offering a wide range of interesting properties. Chemistry plays a major role in the elaboration and comprehension of such materials. The mild chemical conditions allowed by the sol-gel process provide a very versatile access to these hybrid compounds. Sol-gel chemistry allows the adjustment of the degree of interpenetration of organic and inorganic components from the sub-micronic range down to the nano scale level. Consequently, it provides an easy method to synthesize new nano-composites. The hybrid networks can be conveniently divided into two general classes. Class I corresponds to hybrid systems in which organic molecules, oligomers, or low molecular weight organic polymers are simply embedded in the inorganic matrices. in this class, both components exchange rather weak bonds, mainly through van der Waals, hydrogen, or ionic interactions. Class II corresponds to hybrid organic-inorganic compounds where organic and inorganic components are bonded through stronger covalent or iono-covalent chemical bonds. These organic components bonded to the inorganic network can play two main roles: network modifiers or network formers. A critical review of the chemical design of these hybrid organic-inorganic networks synthesized via sol-gel chemistry is presented.