PLASMA THIN FILMS PREVENTING CHLORIDE LONS FROM INTERFERING WITH THE NERNSTIAN pH-RESPONSE OF PLATINUM ELECTRODE SURFACE

The plasma-deposited polymer thin films at platinum surface were investigated as materials blocking access of chloride ions to the platinum surface and preventing their interference with the Nernstian responce of platinum. In the presence of chloride ions, the pH response of a naked platinum was remarkably affected. By comparison of pH responses of coated and uncoated platinum-wire electrodes immersed in solutions with chloride ions, it was found that toluene and ethylbenzene plasma films could improve the pH response of platinum. The pH response of coated platinum electrodes may be explained by the ability of protons, by virtue of their small size, to move through the polymer matrix to the platinum surface.