Hydrogen Permeation through Diamond-Like Carbon Thin Films Coated on PET Sheet

Abstract

Hydrogen (H2) permeation through diamond-like carbon (DLC) thin films has been investigated by using dynamic observation of H2 leakage through the DLC films into a high vacuum chamber equipped with a quadropole mass spectrometer (QMS). DLC films were deposited on polyethylene terephthalate (PET) sheets using radio frequency (RF) plasma chemical vapor deposition (CVD) method from C2H2 source gas. The specimen was set on the flange of an ultra-high vacuum (UHV) chamber and H2 gas was permeated through the sheet. The permeation of H2 through the 0.3 mm thick PET sheet started within a few minutes and became saturated in the permeation rate within a few hours after the pressure difference was applied. With the 100-nm thick DLC coating, the response of H2 permeation was delayed and the permeation rate was decreased.