AMPEROMETRIC ION SENSORS BASED ON LASER-PATTERNED COMPOSITE POLYMER MEMBRANES

A polymer membrane for the selective amperometric transfer and sensing of molecular ions has been designed and characterised. The membrane w as formed from two polymer layers, a supporting film of polyethylene t erephthalate on which an electrolyte film containing polyvinylchloride is cast. The polyester layer has a laser-etched pattern of circular m icro-holes in one region. These hole structures are arranged in a rect angular geometry and measure 22 mu m in diameter with separation dista nces of 105 mu m and 120 mu m. The polyvinylchloride underlayer is a c omposite system comprised of a 2-nitrophenyl octyl ether plasticising solution containing an electrolytic salt of tetrabutylammonium tetraki s-(4-chlorophenyl)borate. In this way, an array of micro-interfaces be tween an analyte solution and a PVC gel electrolyte is formed and used as a liquid/liquid interface for the amperometric monitoring of ion t ransfer reactions. The membrane was characterised in terms of the volt ammetric response to choline transfer. The study includes an examinati on of the fabrication methodology, materials composition and membrane structure. (C) 1997 Elsevier Science S.A.