Hybrid Organic-Inorganic Electrode-Membranes Based on Organo-Polysiloxane/Macrocycle Systems

Abstract

Specific complexing agents for alkaline ions such as some crown-ethers of different intramolecular cavity size (12-crown-4, 15-crown-5 and 18-crown-6) are incorporated into a organo-polyorganosiloxane network generated via the sol-gel process. The resulting xerogels embody macrocycle compounds with different ion-selectivity. These xerogels are deposited onto porous supports (borosilicate, polyacrylonitrile,…) to obtain new composite electrode- membranes. The electrochemical characterization of the membranes and the electrode- membranes by electrochemical impedance spectroscopy (EIS) shows information about the reversible behavior and the ion resistance of the membranes, which are a function of both, nature and content of the entrapped macrocycle as well as the salt solution concentration. The electrochemical response of these systems acting as electrode-membranes shows their sensitivity towards different metal ions at variable concentrations.