Effect of surface oxidation treatments on DC charge injection into polyethylene from aqueous electrolytes

Polyethylene film contacted with 1M H₂SO₄ + 1M FeCl₃ on one side and 1M NaCl on the other has been shown to transport higher current densities when polarized than polyethylene contacted by 1M NaCl on both sides [3] or by polyethylene contacted on both sides by metal electrodes. The reason for this enhanced current density was examined through the use of current-voltage (I-V) tests following different pretreatments of the polyethylene films with ferric chloride electrolytes. The ferric chloride solutions in the pretreatment introduce chemical changes to the surface of polyethylene. The surface changes were evaluated with X-ray photoelectron spectroscopy and fluorescence spectroscopy. Both spectroscopic techniques identified increased carbonyl group concentration in the areas of polyethylene that were exposed to 1M H₂SO₄ + 1M FeCl₃. These carbonyl groups are thought to aid in the charge injection process.