A novel technique to enhance surface properties of DLC films deposited on the inner wall of cylindrical PET barrel by DC-RF hybrid discharge

► A newly proposed technique has been utilized to improve surface properties of gas barriering DLC films deposited on PET bottle. ► The gas permeability of DLC coated PET samples deposited with external bias has been substantially decreased compared to that of untreated one. ► Diamond like carbon films have been fabricated on PET barrel using the novel technique based RF PECVD with an external DC bias. ► By coupling with an external negative DC bias, the films tend to be more resistant to damage during immersion test in the beer at room temperature. ► There exists a proper bias to give rise to a small surface roughness.