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Abstract. Two families of hybrid organic-inorganic composites exhibiting Li + ionic conduction (ORMOLYTES) have been prepared by the sol-gel process. The first family, prepared from a mixture of 3-isocyanatopropyltriethoxysilane, O,O' Bis (2-aminopropyl)-polyethyleneglycol (or O,O' Bis (2-aminopropyl)-polypropyleneglycol) and lithium salt, presents chemical bonds between the organic and the inorganic phase and an ionic conductivity cr higher than 10 -4 S m -1 at room temperature. Their properties have been related to their structure using liquid state NMR measurements of 7Li between -100~ and + 100~ and the DMTA technique. In the second family, prepared by ultrasonic method from a mixture of tetraethoxysilane (TEOS), polyethyleneglycol (PEG) and lithium salt, the organic and inorganic phases are not chemically bonded. Ionic conductivity ~r has been studied as a function of the polymer chain length and concentration. Values of or up to 10 -2 S m -i at room temperature have been obtained (with a silica-PEG30o system, PEG/TEOS = 40% in weight). Again, structure was investigated by liquid state 7Li NMR measurements.

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