ORGANOSILICIC MEMBRANES DOPED WITH CROWN-ETHERS

Composite membranes have been prepared via the sol-gel process by cont rolled hydrolysis of ethyltriethoxysilane incorporating in the sol pha se a selected crown-ether. The membranes are supported on borosilicate porous discs forming a continuous network as shown by scanning electr on microscopy. The crown-ether (12-crown-4, 15-crown-5, 18-crown-6) re mains homogeneously distributed in the organosilicic matrix as evidenc ed by IR and C-13 NMR spectroscopies. A C. impedance plots vary with t he nature of the doped crown-ether as well as with the electrolyte use d (alkali-metal chloride aqueous solutions).