Preparation and characterization of an electronically conductive and chemically modified ultrafiltration type membrane

We have prepared, for the first time, an electronically conductive polyethersulfone ultrafiltration membrane, noted as PS, by depositing an ultrathin gold coating. This conductive membrane has been chemically modified by electrodepositing a polymer-based nickel tetrasulfonated phthalocyanine film (NiTSPc) covered by Nafion^®. Atomic force microscopy (AFM) and membrane potential measurement experiments were carried out to characterize the morphology and the transport properties of the new PS membrane. AFM measurements showed that the topology of the surface pores of the PS membrane was modified by the deposition of Au, NiTSPc and Nafion^® layers and that the chemical modifications of the membrane do not obstruct the access to the inner pores. Li⁺ transport number determination have corroborated AFM results and showed that the Li⁺ transport was facilitated by electrostatic effect induced by the negative charge densities of NiTSPc and NiTSPc/Nafion^® coatings.